-- The value size is an integer (Int), defined to be
-- the sum of twelve and thirteen.
size :: Int
size = 12 + 13
-- The function to square an integer.
square :: Int -> Int
square n = n * n
-- The function to double an integer.
double :: Int -> Int
double n = 2 * n
-- An example using double, square, and size.
example :: Int
example = double (size - square (2 + 2))