//01 Matrix
#include<bits/stdc++.h>
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;
}