x(u,v) = cos(v) cos(u)
y(u,v) = sin(v) cos(u)
z(u,v) = (1 - a v) sin(u)
where:
- u ranges from -ð/2 to ð/2, scanning a half circle from the pointed tip at top to the pointed tip at bottom.
- v ranges from 0 to 6ð, scanning a full circle on the XY-plane three times, producing the three snails which meet each other face-to-face (each is inside the other).
- a is a parameter ranging from 0.1 to 0.2 and back again to 0.1, with a step of 0.01, giving the 20 frames shown here. If a = 0 the facing snails is reduced to its ancestor, the sphere.
Ancestor: Sphere.
Descendants: Cocoon, Conch, Onion Slice.