#include <bits/stdc++.h>
using namespace std;
void draw(int H, int W);
int main() {
  int H, W;
  while (1) {
    if (H + W == 0) {
      break;
    }
    cin >> H >> W;
    draw(H, W);
    cout << endl;
  }
  return 0;
}
void draw(int H, int W) {
  int size = H * W;
  char before = '.';
  for (int i = 0; i < size; i++) {
    if (i == 0 || before == '.') {
      before = '#';
      cout << '#';
    } else {
      before = '.';
      cout << '.';
    }
    if ((i + 1) % W == 0) {
      cout << endl;
    }
  }
}
