#include <bits/stdc++.h>
using namespace std;
int main() {
  int H[1000], W[1000];
  int i, j, k, l, m, p, q, r, s, t, u, num1 = 1, num2 = 1;
  H[0] = -1;
  W[0] = -1;
  while (H[num1 - 1] != 0 && W[num1 - 1] != 0) {
    cin >> H[num1];
    cin >> W[num1];
    num1 = num1 + 1;
  }
  while (H[num2] != 0 && W[num2] != 0) {
    if (W[num2] % 2 == 0 && H[num2] % 2 == 0) {
      for (i = 0; i < H[num2] / 2; i++) {
        for (j = 0; j < W[num2] / 2; j++) {
          cout << "#.";
        }
        cout << endl;
        for (m = 0; m < W[num2] / 2; m++) {
          cout << ".#";
        }
        cout << endl;
      }
      cout << endl;
      num2++;
    } else if (W[num2] % 2 == 0 && H[num2] % 2 == 1) {
      for (i = 0; i < H[num2] / 2; i++) {
        for (j = 0; j < W[num2] / 2; j++) {
          cout << "#.";
        }
        cout << endl;
        for (m = 0; m < W[num2] / 2; m++) {
          cout << ".#";
        }
        cout << endl;
      }
      for (p = 0; p < W[num2] / 2; p++) {
        cout << "#.";
      }
      cout << endl;
      cout << endl;
      num2++;
    } else if (W[num2] % 2 == 1 && H[num2] % 2 == 0) {
      for (k = 0; k < H[num2] / 2; k++) {
        for (l = 0; l < W[num2] / 2; l++) {
          cout << "#.";
        }
        cout << "#" << endl;
        for (q = 0; q < W[num2] / 2; q++) {
          cout << ".#";
        }
        cout << "." << endl;
      }
      cout << endl;
      cout << endl;
      num2++;
    } else {
      for (s = 0; s < H[num2] / 2; s++) {
        for (t = 0; t < W[num2] / 2; t++) {
          cout << "#.";
        }
        cout << "#" << endl;
        for (u = 0; u < W[num2] / 2; u++) {
          cout << ".#";
        }
        cout << "." << endl;
      }
      for (r = 0; r < W[num2] / 2; r++) {
        cout << "#.";
      }
      cout << "#" << endl;
      cout << endl;
      num2++;
    }
  }
}
