import std.stdio, std.conv, std.string, std.range, std.algorithm, std.array,
  std.functional, std.container, std.typecons;

void main() {
  auto input = readln.split.to!(int[]);
  int H = input[0], W = input[1], A = input[2], B = input[3];

  bool[] reversed = new bool[H];
  foreach(i; 0..B) {
    reversed[i] = true;
  }

  foreach(i; 0..H) {
    foreach(j; 0..A) {
      write(reversed[i] ? 0 : 1);
    }
    foreach(j; A..W) {
      write(reversed[i] ? 1 : 0);
    }
    writeln;
  }
}
