#http://mathworld.wolfram.com/TetrahedralSurface.html

vertices = D1:100 D2:100

u = from -2 to 2 D1
v = from -2 to 2 D2

a = rand2(-1, 1)
b = rand2(-1, 1)
c = rand2(-1, 1)

m = rand2(0.2, 5)
n = rand2(0.2, 5)

x = pow_sign(u - a, m)*pow_sign(v - a, n)
z = pow_sign(u - b, m)*pow_sign(v - b, n)
y = pow_sign(u - c, m)*pow_sign(v - c, n)

