import Test.QuickCheck

square :: Integer -> Integer
square x  =  x * x

pyth :: Integer -> Integer -> Integer
pyth a b =  square a + square b

prop_square :: Integer -> Bool
prop_square x  =
  square x >= 0

prop_squares :: Integer -> Integer -> Bool
prop_squares x y  =
  square (x+y) == square x + 2*x*y + square y

prop_pyth :: Integer -> Integer -> Bool
prop_pyth x y  =
  square (x+y) == pyth x y + 2*x*y