The list monad is awesome

sqrtM x = [sqrt x, -sqrt x]

addOne x = return $ x + 1

f x = do y <- sqrtM x
         z <- addOne y
         sqrtM z

*Main> f 0.5
[1.3065629648763766,-1.3065629648763766,0.5411961001461969,-0.5411961001461969]

<-- ultimate dubs
12 is dubs in base 11, which is dubs in base 10, which is dubs in base 9, which is dubs in base 8, which is dubs in base 7, which is dubs in base 6, which is dubs in base 5, which is dubs in base 4, which is dubs in base 3, which is dubs in binary.