x = 2 sin(3 u) / (2 + cos(v))
y = 2 (sin(u) + 2 sin(2 u)) / (2 + cos(v + 2 Pi / 3))
z = (cos(u) - 2 cos(2 u)) (2 + cos(v)) (2 + cos(v + 2 Pi / 3)) / 4