#include <bits/stdc++.h>
using namespace std;
int subf(int, int);
int H, W;
int main() {
  while (1) {
    cin >> H >> W;
    if (H == 0 && W == 0) {
      break;
    } else {
      subf(H, W);
    }
  }
  return 0;
}
int subf(int h, int w) {
  int j, k = 0;
  while (1) {
    if (k > h) {
      break;
    } else {
      while (k <= h) {
        while (j <= w) {
          cout << "#";
          j++;
          if (j <= W) {
            cout << ".";
            j++;
          }
        }
        puts("");
        k++;
        j = 0;
        break;
      }
      while (k <= h) {
        while (j <= w) {
          cout << ".";
          j++;
          if (j <= W) {
            cout << "#";
            j++;
          }
        }
        puts("");
        k++;
        j = 0;
        break;
      }
    }
  }
  return 0;
}
