let () = Scanf.sscanf (read_line ()) "%d %d %d %d" @@ fun h w a b ->
  for i = 0 to h - 1 do
    for j = 0 to w - 1 do
      print_int @@ 
        if i < b then
          if j < a then 0 else 1
        else
          if j < a then 1 else 0
    done;
    print_newline ()
  done