import Foundation

func readWords<T>(_ f: (Substring) -> T) -> [T] {
    return readLine()!.split(separator: " ").map(f)
}

func main() {
    var hwab = readWords { Int($0)! }.makeIterator()
    let h = hwab.next()!
    let w = hwab.next()!
    let a = hwab.next()!
    let b = hwab.next()!

    var box = ("0", "1")

    for i in 1...h {
        print(String(repeating: box.0, count: w-a) + String(repeating: box.1, count: a))
        if i == b{
            box = ("1", "0")
        }
    }
}

main()