#include <iostream>

using namespace std;

int main() {
  int h, w, a, b;
  cin >> h >> w >> a >> b;
  for (int i = 0; i < h; ++i) {
    for (int j = 0; j < w; ++j) {
    	cout << ((i < b) ^ (j < a));
    }
    cout << endl;
  }
  return 0;
}