#include<iostream>
#include<vector>
using namespace std;
int main() {
  long long H,W,K;
  cin >> H >> W >> K;
  vector<vector<int>> m(H,vector<int>(W,0));
  int x = 0,y = 0,dx = 1,dy = 1,t = 0;
  do {
    m[x][y] = 1-m[x][y];
    if(x == 0 && dx == -1)dx = 1;
    else if(x == H-1 && dx == 1)dx = -1;
    else x += dx;
    if(y == 0 && dy == -1)dy = 1;
    else if(y == W-1 && dy == 1)dy = -1;
    else y += dy;
    t++;
  } while(x != 0 || y != 0 || m[0][0]);
  K %= t;
  while(K--) {
    m[x][y] = 1-m[x][y];
    if(x == 0 && dx == -1)dx = 1;
    else if(x == H-1 && dx == 1)dx = -1;
    else x += dx;
    if(y == 0 && dy == -1)dy = 1;
    else if(y == W-1 && dy == 1)dy = -1;
    else y += dy;
  }
  for(int i=0;i<H;i++) {
    for(int j=0;j<W;j++)cout << (m[i][j]?'#':'.');
    cout << endl;
  }
}