hshyper 0 a b = succ b
hyper 1 a 0 = a
hyper 2 a 0 = 0
hyper n a 0 = 1
hyper n a b = hyper (n-1) a $ hyper n a (b-1) hsinc = hyper 0 -- inc _ 1 == 2
add = hyper 1 -- add 1 2 == 1+2
mul = hyper 2 -- mul 1 2 == 1*2
pow = hyper 3 -- pow 1 2 == 1^2
tet = hyper 4 --
pen = hyper 5 --