#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, j, k, l, m, h[10000], w[10000];
  char chess1[300], chess2[300];
  for (i = 0; i <= 9999; i++) {
    cin >> h[i] >> w[i];
    if ((h[i] == 0) and (w[i] == 0)) {
      break;
    }
  }
  for (j = 0; j <= i - 1; j++) {
    for (k = 0; k <= w[j] - 1; k += 2) {
      chess1[k] = '#';
      if ((w[j] - k == 1) and (w[j] % 2 == 0)) {
        break;
      }
      chess1[k + 1] = '.';
    }
    for (k = 0; k <= w[j] - 1; k++) {
      switch (chess1[k]) {
        case '#':
          chess2[k] = '.';
          break;
        case '.':
          chess2[k] = '#';
          break;
      }
    }
    for (k = 0; k <= h[j] / 2 - 1; k++) {
      for (l = 0; l <= w[j] - 1; l++) {
        cout << chess1[l];
      }
      cout << endl;
      for (l = 0; l <= w[j] - 1; l++) {
        cout << chess2[l];
      }
      cout << endl;
      if (h[j] - 2 * (k + 1) == 1) {
        for (l = 0; l <= w[j] - 1; l++) {
          cout << chess1[l];
        }
        cout << endl;
      }
    }
    cout << endl;
  }
  return 0;
}
