import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
	public static void main(String[] arges) {
		List<String> klist = new ArrayList<String>();
		int i = 0;
		Scanner sc = new Scanner(System.in);
		while (i < 1) {
			String line = sc.nextLine();
			klist.add(line);
			if (line.equals("0 0")) {
				break;
			}
		}

		for (String string : klist) {
			if (string.equals("0 0")) {
				break;
			}
			String[] k = string.split(" ");
			int v = Integer.parseInt(k[0]);// ???
			int v2 = Integer.parseInt(k[1]);// ?¨?

			for (int j = 0; j < v; j++) {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			}
			System.out.println("");

		}
	}
} import java.util.ArrayList; ArrayList java.util import java.util.List; List java.util import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] arges) {
		List<String> klist = new ArrayList<String>();
		int i = 0;
		Scanner sc = new Scanner(System.in);
		while (i < 1) {
			String line = sc.nextLine();
			klist.add(line);
			if (line.equals("0 0")) {
				break;
			}
		}

		for (String string : klist) {
			if (string.equals("0 0")) {
				break;
			}
			String[] k = string.split(" ");
			int v = Integer.parseInt(k[0]);// ???
			int v2 = Integer.parseInt(k[1]);// ?¨?

			for (int j = 0; j < v; j++) {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			}
			System.out.println("");

		}
	}
} Main public static void main(String[] arges) {
		List<String> klist = new ArrayList<String>();
		int i = 0;
		Scanner sc = new Scanner(System.in);
		while (i < 1) {
			String line = sc.nextLine();
			klist.add(line);
			if (line.equals("0 0")) {
				break;
			}
		}

		for (String string : klist) {
			if (string.equals("0 0")) {
				break;
			}
			String[] k = string.split(" ");
			int v = Integer.parseInt(k[0]);// ???
			int v2 = Integer.parseInt(k[1]);// ?¨?

			for (int j = 0; j < v; j++) {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			}
			System.out.println("");

		}
	} main {
		List<String> klist = new ArrayList<String>();
		int i = 0;
		Scanner sc = new Scanner(System.in);
		while (i < 1) {
			String line = sc.nextLine();
			klist.add(line);
			if (line.equals("0 0")) {
				break;
			}
		}

		for (String string : klist) {
			if (string.equals("0 0")) {
				break;
			}
			String[] k = string.split(" ");
			int v = Integer.parseInt(k[0]);// ???
			int v2 = Integer.parseInt(k[1]);// ?¨?

			for (int j = 0; j < v; j++) {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			}
			System.out.println("");

		}
	} List<String> klist = new ArrayList<String>(); klist new ArrayList<String>() int i = 0; i 0 Scanner sc = new Scanner(System.in); sc new Scanner(System.in) while (i < 1) {
			String line = sc.nextLine();
			klist.add(line);
			if (line.equals("0 0")) {
				break;
			}
		} i < 1 i 1 {
			String line = sc.nextLine();
			klist.add(line);
			if (line.equals("0 0")) {
				break;
			}
		} String line = sc.nextLine(); line sc.nextLine() sc.nextLine sc klist.add(line) klist.add klist line if (line.equals("0 0")) {
				break;
			} line.equals("0 0") line.equals line "0 0" {
				break;
			} break; for (String string : klist) {
			if (string.equals("0 0")) {
				break;
			}
			String[] k = string.split(" ");
			int v = Integer.parseInt(k[0]);// ???
			int v2 = Integer.parseInt(k[1]);// ?¨?

			for (int j = 0; j < v; j++) {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			}
			System.out.println("");

		} String string klist {
			if (string.equals("0 0")) {
				break;
			}
			String[] k = string.split(" ");
			int v = Integer.parseInt(k[0]);// ???
			int v2 = Integer.parseInt(k[1]);// ?¨?

			for (int j = 0; j < v; j++) {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			}
			System.out.println("");

		} {
			if (string.equals("0 0")) {
				break;
			}
			String[] k = string.split(" ");
			int v = Integer.parseInt(k[0]);// ???
			int v2 = Integer.parseInt(k[1]);// ?¨?

			for (int j = 0; j < v; j++) {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			}
			System.out.println("");

		} if (string.equals("0 0")) {
				break;
			} string.equals("0 0") string.equals string "0 0" {
				break;
			} break; String[] k = string.split(" "); k string.split(" ") string.split string " " int v = Integer.parseInt(k[0]); v Integer.parseInt(k[0]) Integer.parseInt Integer k[0] k 0 int v2 = Integer.parseInt(k[1]); v2 Integer.parseInt(k[1]) Integer.parseInt Integer k[1] k 1 for (int j = 0; j < v; j++) {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			} int j = 0; int j = 0; j 0 j < v j v j++ j++ j {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			} {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			} int count = 0; count 0 if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				} (j + 1 )% 2 == 1 (j + 1 )% 2 (j + 1 ) j 1 2 1 {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					} count < v2 count v2 {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					} if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						} (count + 1) % 2 == 1 (count + 1) % 2 (count + 1) count 1 2 1 {
							System.out.print("#");
							count++;
						} System.out.print("#") System.out.print System.out System System.out "#" count++ count {
							System.out.print(".");
							count++;
						} System.out.print(".") System.out.print System.out System System.out "." count++ count {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				} while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					} count < v2 count v2 {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					} if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						} (count + 1) % 2 == 1 (count + 1) % 2 (count + 1) count 1 2 1 {
							System.out.print(".");
							count++;
						} System.out.print(".") System.out.print System.out System System.out "." count++ count {
							System.out.print("#");
							count++;
						} System.out.print("#") System.out.print System.out System System.out "#" count++ count System.out.println("") System.out.println System.out System System.out "" System.out.println("") System.out.println System.out System System.out "" String[] arges arges public class Main {
	public static void main(String[] arges) {
		List<String> klist = new ArrayList<String>();
		int i = 0;
		Scanner sc = new Scanner(System.in);
		while (i < 1) {
			String line = sc.nextLine();
			klist.add(line);
			if (line.equals("0 0")) {
				break;
			}
		}

		for (String string : klist) {
			if (string.equals("0 0")) {
				break;
			}
			String[] k = string.split(" ");
			int v = Integer.parseInt(k[0]);// ???
			int v2 = Integer.parseInt(k[1]);// ?¨?

			for (int j = 0; j < v; j++) {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			}
			System.out.println("");

		}
	}
} public class Main {
	public static void main(String[] arges) {
		List<String> klist = new ArrayList<String>();
		int i = 0;
		Scanner sc = new Scanner(System.in);
		while (i < 1) {
			String line = sc.nextLine();
			klist.add(line);
			if (line.equals("0 0")) {
				break;
			}
		}

		for (String string : klist) {
			if (string.equals("0 0")) {
				break;
			}
			String[] k = string.split(" ");
			int v = Integer.parseInt(k[0]);// ???
			int v2 = Integer.parseInt(k[1]);// ?¨?

			for (int j = 0; j < v; j++) {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			}
			System.out.println("");

		}
	}
} Main
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
	public static void main(String[] arges) {
		List<String> klist = new ArrayList<String>();
		int i = 0;
		Scanner sc = new Scanner(System.in);
		while (i < 1) {
			String line = sc.nextLine();
			klist.add(line);
			if (line.equals("0 0")) {
				break;
			}
		}

		for (String string : klist) {
			if (string.equals("0 0")) {
				break;
			}
			String[] k = string.split(" ");
			int v = Integer.parseInt(k[0]);// ???
			int v2 = Integer.parseInt(k[1]);// ?¨?

			for (int j = 0; j < v; j++) {
				int count = 0;
				if ((j + 1 )% 2 == 1) {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print("#");
							count++;
						} else {
							System.out.print(".");
							count++;
						}
					}
				} else {
					while (count < v2) {
						if ((count + 1) % 2 == 1) {
							System.out.print(".");
							count++;
						} else {
							System.out.print("#");
							count++;
						}
					}
				}
				System.out.println("");
			}
			System.out.println("");

		}
	}
}