import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int H = sc.nextInt();
			int W = sc.nextInt();
			if (H == 0 && W == 0) {
				break;
			}
			if (H % 2 == 0) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
			} else if (H != 1) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} else {
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			}
			System.out.print("\n");
		}
	}
} import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int H = sc.nextInt();
			int W = sc.nextInt();
			if (H == 0 && W == 0) {
				break;
			}
			if (H % 2 == 0) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
			} else if (H != 1) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} else {
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			}
			System.out.print("\n");
		}
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int H = sc.nextInt();
			int W = sc.nextInt();
			if (H == 0 && W == 0) {
				break;
			}
			if (H % 2 == 0) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
			} else if (H != 1) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} else {
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			}
			System.out.print("\n");
		}
	} main {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int H = sc.nextInt();
			int W = sc.nextInt();
			if (H == 0 && W == 0) {
				break;
			}
			if (H % 2 == 0) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
			} else if (H != 1) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} else {
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			}
			System.out.print("\n");
		}
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) while (true) {
			int H = sc.nextInt();
			int W = sc.nextInt();
			if (H == 0 && W == 0) {
				break;
			}
			if (H % 2 == 0) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
			} else if (H != 1) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} else {
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			}
			System.out.print("\n");
		} true {
			int H = sc.nextInt();
			int W = sc.nextInt();
			if (H == 0 && W == 0) {
				break;
			}
			if (H % 2 == 0) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
			} else if (H != 1) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} else {
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			}
			System.out.print("\n");
		} int H = sc.nextInt(); H sc.nextInt() sc.nextInt sc int W = sc.nextInt(); W sc.nextInt() sc.nextInt sc if (H == 0 && W == 0) {
				break;
			} H == 0 && W == 0 H == 0 H 0 W == 0 W 0 {
				break;
			} break; if (H % 2 == 0) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
			} else if (H != 1) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} else {
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} H % 2 == 0 H % 2 H 2 0 {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
			} for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				} int i = 1; int i = 1; i 1 i <= H / 2 i H / 2 H 2 i++ i++ i {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				} {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				} if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					} W % 2 == 0 W % 2 W 2 0 {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						} int j = 1; int j = 1; j 1 j <= W / 2 j W / 2 W 2 j++ j++ j {
							System.out.print("#.");
						} {
							System.out.print("#.");
						} System.out.print("#.") System.out.print System.out System System.out "#." System.out.print("\n") System.out.print System.out System System.out "\n" for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						} int k = 1; int k = 1; k 1 k <= W / 2 k W / 2 W 2 k++ k++ k {
							System.out.print(".#");
						} {
							System.out.print(".#");
						} System.out.print(".#") System.out.print System.out System System.out ".#" System.out.print("\n") System.out.print System.out System System.out "\n" if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					} W != 1 W 1 {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						} int j = 1; int j = 1; j 1 j <= W / 2 j W / 2 W 2 j++ j++ j {
							System.out.print("#.");
						} {
							System.out.print("#.");
						} System.out.print("#.") System.out.print System.out System System.out "#." System.out.print("#\n") System.out.print System.out System System.out "#\n" for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						} int k = 1; int k = 1; k 1 k <= W / 2 k W / 2 W 2 k++ k++ k {
							System.out.print(".#");
						} {
							System.out.print(".#");
						} System.out.print(".#") System.out.print System.out System System.out ".#" System.out.printf(".\n") System.out.printf System.out System System.out ".\n" {
						System.out.print("#\n");
						System.out.print(".\n");
					} System.out.print("#\n") System.out.print System.out System System.out "#\n" System.out.print(".\n") System.out.print System.out System System.out ".\n" if (H != 1) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} else {
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} H != 1 H 1 {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				} int i = 1; int i = 1; i 1 i <= H / 2 i H / 2 H 2 i++ i++ i {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				} {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				} if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					} W % 2 == 0 W % 2 W 2 0 {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						} int j = 1; int j = 1; j 1 j <= W / 2 j W / 2 W 2 j++ j++ j {
							System.out.print("#.");
						} {
							System.out.print("#.");
						} System.out.print("#.") System.out.print System.out System System.out "#." System.out.print("\n") System.out.print System.out System System.out "\n" for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						} int k = 1; int k = 1; k 1 k <= W / 2 k W / 2 W 2 k++ k++ k {
							System.out.print(".#");
						} {
							System.out.print(".#");
						} System.out.print(".#") System.out.print System.out System System.out ".#" System.out.print("\n") System.out.print System.out System System.out "\n" if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					} W != 1 W 1 {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						} int j = 1; int j = 1; j 1 j <= W / 2 j W / 2 W 2 j++ j++ j {
							System.out.print("#.");
						} {
							System.out.print("#.");
						} System.out.print("#.") System.out.print System.out System System.out "#." System.out.print("#\n") System.out.print System.out System System.out "#\n" for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						} int k = 1; int k = 1; k 1 k <= W / 2 k W / 2 W 2 k++ k++ k {
							System.out.print(".#");
						} {
							System.out.print(".#");
						} System.out.print(".#") System.out.print System.out System System.out ".#" System.out.printf(".\n") System.out.printf System.out System System.out ".\n" {
						System.out.print("#\n");
						System.out.print(".\n");
					} System.out.print("#\n") System.out.print System.out System System.out "#\n" System.out.print(".\n") System.out.print System.out System System.out ".\n" if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				} W % 2 == 0 W % 2 W 2 0 {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					} int j = 1; int j = 1; j 1 j <= W / 2 j W / 2 W 2 j++ j++ j {
						System.out.print("#.");
					} {
						System.out.print("#.");
					} System.out.print("#.") System.out.print System.out System System.out "#." System.out.print("\n") System.out.print System.out System System.out "\n" if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				} W != 1 W 1 {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					} int j = 1; int j = 1; j 1 j <= W / 2 j W / 2 W 2 j++ j++ j {
						System.out.print("#.");
					} {
						System.out.print("#.");
					} System.out.print("#.") System.out.print System.out System System.out "#." System.out.print("#\n") System.out.print System.out System System.out "#\n" {
					System.out.print("#\n");
				} System.out.print("#\n") System.out.print System.out System System.out "#\n" {
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				} W % 2 == 0 W % 2 W 2 0 {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					} int j = 1; int j = 1; j 1 j <= W / 2 j W / 2 W 2 j++ j++ j {
						System.out.print("#.");
					} {
						System.out.print("#.");
					} System.out.print("#.") System.out.print System.out System System.out "#." System.out.print("\n") System.out.print System.out System System.out "\n" if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				} W != 1 W 1 {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					} int j = 1; int j = 1; j 1 j <= W / 2 j W / 2 W 2 j++ j++ j {
						System.out.print("#.");
					} {
						System.out.print("#.");
					} System.out.print("#.") System.out.print System.out System System.out "#." System.out.print("#\n") System.out.print System.out System System.out "#\n" {
					System.out.print("#\n");
				} System.out.print("#\n") System.out.print System.out System System.out "#\n" System.out.print("\n") System.out.print System.out System System.out "\n" String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int H = sc.nextInt();
			int W = sc.nextInt();
			if (H == 0 && W == 0) {
				break;
			}
			if (H % 2 == 0) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
			} else if (H != 1) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} else {
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			}
			System.out.print("\n");
		}
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int H = sc.nextInt();
			int W = sc.nextInt();
			if (H == 0 && W == 0) {
				break;
			}
			if (H % 2 == 0) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
			} else if (H != 1) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} else {
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			}
			System.out.print("\n");
		}
	}
} Main
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (true) {
			int H = sc.nextInt();
			int W = sc.nextInt();
			if (H == 0 && W == 0) {
				break;
			}
			if (H % 2 == 0) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
			} else if (H != 1) {
				for (int i = 1; i <= H / 2; i++) {
					if (W % 2 == 0) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.print("\n");
					} else if (W != 1) {
						for (int j = 1; j <= W / 2; j++) {
							System.out.print("#.");
						}
						System.out.print("#\n");
						for (int k = 1; k <= W / 2; k++) {
							System.out.print(".#");
						}
						System.out.printf(".\n");
					} else {
						System.out.print("#\n");
						System.out.print(".\n");
					}
				}
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			} else {
				if (W % 2 == 0) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("\n");
				} else if (W != 1) {
					for (int j = 1; j <= W / 2; j++) {
						System.out.print("#.");
					}
					System.out.print("#\n");
				} else {
					System.out.print("#\n");
				}
			}
			System.out.print("\n");
		}
	}
}