import Control.Monad

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