x = [True, False]
y = [False, True]
z = x + y

property p1 = z == 3

xx = [[True,False]]
yy = [[False, True]]
zz = xx + yy



t : {a} [a*3] -> [a*3][a*3]
t d = zero
/*


t1 : [8] -> [2][2][2]
t1 x = split (split x)

t2 : [8] -> ([4],[4])
t2 x = splitAt x

t3 : [8] ->[8] -> [16]
t3 x y = x # y

*/