#include <bits/stdc++.h>
using namespace std;
int main() {
  int H, W, i, j, a, b;
  char x[H][W];
  while (1) {
    cin >> H >> W;
    if (H == 0 && W == 0) break;
    for (i = 0; i < H; i++) {
      for (j = 0; j < W; j++) {
        if (i == 0 && j == 0) {
          cout << '#';
          x[i][j] = '#';
        }
        if (x[i][j - 1] == '#') {
          cout << ".";
          x[i][j] = '.';
        } else if (x[i][j - 1] == '.') {
          cout << "#";
          x[i][j] = '#';
        } else if (i > 0 && x[i - 1][0] == '#') {
          cout << ".";
          x[i][j] = '.';
        } else if (i > 0 && x[i - 1][0] == '.') {
          cout << "#";
          x[i][j] = '#';
        }
      }
      cout << endl;
    }
    cout << endl;
  }
}
