#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, t, m;
  t = 0;
  m = 0;
  while (1) {
    cin >> a >> b;
    if (a == 0 && b == 0) {
      cout << endl;
      return 0;
    }
    while (1) {
      while (1) {
        cout << "#";
        m++;
        if (m == b) {
          cout << endl;
          m = 0;
          break;
        }
        cout << ".";
        m++;
        if (m == b) {
          cout << endl;
          m = 0;
          break;
        }
      }
      t++;
      if (t == a) {
        cout << endl;
        m = 0;
        t = 0;
        break;
      }
      while (1) {
        cout << ".";
        m++;
        if (m == b) {
          cout << endl;
          m = 0;
          break;
        }
        cout << "#";
        m++;
        if (m == b) {
          cout << endl;
          m = 0;
          break;
        }
      }
      t++;
      if (t == a) {
        cout << endl;
        m = 0;
        t = 0;
        break;
      }
    }
  }
  return 0;
}
