
import java.util.Scanner;

class Main {
	public static void main(String[] args) {
		// Scanner scanner = new Scanner("3 5 4 2 0 0 8 8");
		Scanner scanner = new Scanner(System.in);
		int h;
		int w;
		while (true) {
			h = scanner.nextInt();
			w = scanner.nextInt();
			if (h == 0 && w == 0) {
				break;
			}
			if (0 == h % 2) {
				for (int i = 0; i < (h / 2); i++) {
					lineMaker01(w);
					lineMaker02(w);
				}
			} else {
				for (int j = 0; j < (h / 2); j++) {
					lineMaker01(w);
					lineMaker02(w);
				}
				lineMaker01(w);
			}
			System.out.println("");
		}
		// System.out.println("");
	}

	static void lineMaker01(int w) { // #.#. ??¶??°?????´???
		if (0 == w % 2) {
			for (int i = 0; i < w / 2; i++) {
				System.out.print("#");
				System.out.print(".");
			}
		} else {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print("#");
				System.out.print(".");
			}
			System.out.print("#");
		}
		System.out.println("");
	}

	static void lineMaker02(int w) { // .#.# ?\???°?????´???
		if (0 == w % 2) {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
		} else {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
			System.out.print(".");
		}
		System.out.println("");

	}

} import java.util.Scanner; Scanner java.util class Main {
	public static void main(String[] args) {
		// Scanner scanner = new Scanner("3 5 4 2 0 0 8 8");
		Scanner scanner = new Scanner(System.in);
		int h;
		int w;
		while (true) {
			h = scanner.nextInt();
			w = scanner.nextInt();
			if (h == 0 && w == 0) {
				break;
			}
			if (0 == h % 2) {
				for (int i = 0; i < (h / 2); i++) {
					lineMaker01(w);
					lineMaker02(w);
				}
			} else {
				for (int j = 0; j < (h / 2); j++) {
					lineMaker01(w);
					lineMaker02(w);
				}
				lineMaker01(w);
			}
			System.out.println("");
		}
		// System.out.println("");
	}

	static void lineMaker01(int w) { // #.#. ??¶??°?????´???
		if (0 == w % 2) {
			for (int i = 0; i < w / 2; i++) {
				System.out.print("#");
				System.out.print(".");
			}
		} else {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print("#");
				System.out.print(".");
			}
			System.out.print("#");
		}
		System.out.println("");
	}

	static void lineMaker02(int w) { // .#.# ?\???°?????´???
		if (0 == w % 2) {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
		} else {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
			System.out.print(".");
		}
		System.out.println("");

	}

} Main public static void main(String[] args) {
		// Scanner scanner = new Scanner("3 5 4 2 0 0 8 8");
		Scanner scanner = new Scanner(System.in);
		int h;
		int w;
		while (true) {
			h = scanner.nextInt();
			w = scanner.nextInt();
			if (h == 0 && w == 0) {
				break;
			}
			if (0 == h % 2) {
				for (int i = 0; i < (h / 2); i++) {
					lineMaker01(w);
					lineMaker02(w);
				}
			} else {
				for (int j = 0; j < (h / 2); j++) {
					lineMaker01(w);
					lineMaker02(w);
				}
				lineMaker01(w);
			}
			System.out.println("");
		}
		// System.out.println("");
	} main {
		// Scanner scanner = new Scanner("3 5 4 2 0 0 8 8");
		Scanner scanner = new Scanner(System.in);
		int h;
		int w;
		while (true) {
			h = scanner.nextInt();
			w = scanner.nextInt();
			if (h == 0 && w == 0) {
				break;
			}
			if (0 == h % 2) {
				for (int i = 0; i < (h / 2); i++) {
					lineMaker01(w);
					lineMaker02(w);
				}
			} else {
				for (int j = 0; j < (h / 2); j++) {
					lineMaker01(w);
					lineMaker02(w);
				}
				lineMaker01(w);
			}
			System.out.println("");
		}
		// System.out.println("");
	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int h; h int w; w while (true) {
			h = scanner.nextInt();
			w = scanner.nextInt();
			if (h == 0 && w == 0) {
				break;
			}
			if (0 == h % 2) {
				for (int i = 0; i < (h / 2); i++) {
					lineMaker01(w);
					lineMaker02(w);
				}
			} else {
				for (int j = 0; j < (h / 2); j++) {
					lineMaker01(w);
					lineMaker02(w);
				}
				lineMaker01(w);
			}
			System.out.println("");
		} true {
			h = scanner.nextInt();
			w = scanner.nextInt();
			if (h == 0 && w == 0) {
				break;
			}
			if (0 == h % 2) {
				for (int i = 0; i < (h / 2); i++) {
					lineMaker01(w);
					lineMaker02(w);
				}
			} else {
				for (int j = 0; j < (h / 2); j++) {
					lineMaker01(w);
					lineMaker02(w);
				}
				lineMaker01(w);
			}
			System.out.println("");
		} h = scanner.nextInt() h scanner.nextInt() scanner.nextInt scanner w = scanner.nextInt() w scanner.nextInt() scanner.nextInt scanner if (h == 0 && w == 0) {
				break;
			} h == 0 && w == 0 h == 0 h 0 w == 0 w 0 {
				break;
			} break; if (0 == h % 2) {
				for (int i = 0; i < (h / 2); i++) {
					lineMaker01(w);
					lineMaker02(w);
				}
			} else {
				for (int j = 0; j < (h / 2); j++) {
					lineMaker01(w);
					lineMaker02(w);
				}
				lineMaker01(w);
			} 0 == h % 2 0 h % 2 h 2 {
				for (int i = 0; i < (h / 2); i++) {
					lineMaker01(w);
					lineMaker02(w);
				}
			} for (int i = 0; i < (h / 2); i++) {
					lineMaker01(w);
					lineMaker02(w);
				} int i = 0; int i = 0; i 0 i < (h / 2) i (h / 2) h 2 i++ i++ i {
					lineMaker01(w);
					lineMaker02(w);
				} {
					lineMaker01(w);
					lineMaker02(w);
				} lineMaker01(w) lineMaker01 w lineMaker02(w) lineMaker02 w {
				for (int j = 0; j < (h / 2); j++) {
					lineMaker01(w);
					lineMaker02(w);
				}
				lineMaker01(w);
			} for (int j = 0; j < (h / 2); j++) {
					lineMaker01(w);
					lineMaker02(w);
				} int j = 0; int j = 0; j 0 j < (h / 2) j (h / 2) h 2 j++ j++ j {
					lineMaker01(w);
					lineMaker02(w);
				} {
					lineMaker01(w);
					lineMaker02(w);
				} lineMaker01(w) lineMaker01 w lineMaker02(w) lineMaker02 w lineMaker01(w) lineMaker01 w System.out.println("") System.out.println System.out System System.out "" String[] args args static void lineMaker01(int w) { // #.#. ??¶??°?????´???
		if (0 == w % 2) {
			for (int i = 0; i < w / 2; i++) {
				System.out.print("#");
				System.out.print(".");
			}
		} else {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print("#");
				System.out.print(".");
			}
			System.out.print("#");
		}
		System.out.println("");
	} lineMaker01 { // #.#. ??¶??°?????´???
		if (0 == w % 2) {
			for (int i = 0; i < w / 2; i++) {
				System.out.print("#");
				System.out.print(".");
			}
		} else {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print("#");
				System.out.print(".");
			}
			System.out.print("#");
		}
		System.out.println("");
	} if (0 == w % 2) {
			for (int i = 0; i < w / 2; i++) {
				System.out.print("#");
				System.out.print(".");
			}
		} else {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print("#");
				System.out.print(".");
			}
			System.out.print("#");
		} 0 == w % 2 0 w % 2 w 2 {
			for (int i = 0; i < w / 2; i++) {
				System.out.print("#");
				System.out.print(".");
			}
		} for (int i = 0; i < w / 2; i++) {
				System.out.print("#");
				System.out.print(".");
			} int i = 0; int i = 0; i 0 i < w / 2 i w / 2 w 2 i++ i++ i {
				System.out.print("#");
				System.out.print(".");
			} {
				System.out.print("#");
				System.out.print(".");
			} System.out.print("#") System.out.print System.out System System.out "#" System.out.print(".") System.out.print System.out System System.out "." {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print("#");
				System.out.print(".");
			}
			System.out.print("#");
		} for (int i = 0; i < (w / 2); i++) {
				System.out.print("#");
				System.out.print(".");
			} int i = 0; int i = 0; i 0 i < (w / 2) i (w / 2) w 2 i++ i++ i {
				System.out.print("#");
				System.out.print(".");
			} {
				System.out.print("#");
				System.out.print(".");
			} System.out.print("#") System.out.print System.out System System.out "#" System.out.print(".") System.out.print System.out System System.out "." System.out.print("#") System.out.print System.out System System.out "#" System.out.println("") System.out.println System.out System System.out "" int w w static void lineMaker02(int w) { // .#.# ?\???°?????´???
		if (0 == w % 2) {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
		} else {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
			System.out.print(".");
		}
		System.out.println("");

	} lineMaker02 { // .#.# ?\???°?????´???
		if (0 == w % 2) {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
		} else {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
			System.out.print(".");
		}
		System.out.println("");

	} if (0 == w % 2) {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
		} else {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
			System.out.print(".");
		} 0 == w % 2 0 w % 2 w 2 {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
		} for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			} int i = 0; int i = 0; i 0 i < (w / 2) i (w / 2) w 2 i++ i++ i {
				System.out.print(".");
				System.out.print("#");
			} {
				System.out.print(".");
				System.out.print("#");
			} System.out.print(".") System.out.print System.out System System.out "." System.out.print("#") System.out.print System.out System System.out "#" {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
			System.out.print(".");
		} for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			} int i = 0; int i = 0; i 0 i < (w / 2) i (w / 2) w 2 i++ i++ i {
				System.out.print(".");
				System.out.print("#");
			} {
				System.out.print(".");
				System.out.print("#");
			} System.out.print(".") System.out.print System.out System System.out "." System.out.print("#") System.out.print System.out System System.out "#" System.out.print(".") System.out.print System.out System System.out "." System.out.println("") System.out.println System.out System System.out "" int w w

import java.util.Scanner;

class Main {
	public static void main(String[] args) {
		// Scanner scanner = new Scanner("3 5 4 2 0 0 8 8");
		Scanner scanner = new Scanner(System.in);
		int h;
		int w;
		while (true) {
			h = scanner.nextInt();
			w = scanner.nextInt();
			if (h == 0 && w == 0) {
				break;
			}
			if (0 == h % 2) {
				for (int i = 0; i < (h / 2); i++) {
					lineMaker01(w);
					lineMaker02(w);
				}
			} else {
				for (int j = 0; j < (h / 2); j++) {
					lineMaker01(w);
					lineMaker02(w);
				}
				lineMaker01(w);
			}
			System.out.println("");
		}
		// System.out.println("");
	}

	static void lineMaker01(int w) { // #.#. ??¶??°?????´???
		if (0 == w % 2) {
			for (int i = 0; i < w / 2; i++) {
				System.out.print("#");
				System.out.print(".");
			}
		} else {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print("#");
				System.out.print(".");
			}
			System.out.print("#");
		}
		System.out.println("");
	}

	static void lineMaker02(int w) { // .#.# ?\???°?????´???
		if (0 == w % 2) {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
		} else {
			for (int i = 0; i < (w / 2); i++) {
				System.out.print(".");
				System.out.print("#");
			}
			System.out.print(".");
		}
		System.out.println("");

	}

}