#include <iostream>
#define rep(i, n) for (int i = 0; i < (n); i++)

using namespace std;

int main() {
  int h, w, a, b;
  cin >> h >> w >> a >> b;
  rep(i, h) {
    rep(j, w) {
      if ((i < b) ^ (j < a))
        cout << 1;
      else
        cout << 0;
    }
    cout << endl;
  }
}
