import Data.List
import Control.Monad

main = do
    [h,w,a,b] <- map read . words <$> getLine :: IO [Int]
    let ans1 = replicate a '0' ++ replicate (w-a) '1'
    let ans2 = replicate a '1' ++ replicate (w-a) '0'
    replicateM_ b $ putStrLn ans1
    replicateM_ (h-b) $ putStrLn ans2