This is a view of Boys Surface from the 'top' side- you can see the 3 'cave entrances'. Directly on the far side is the triple point. This surface is single-sided, and this model is the 'immersion' of the surface into three-space. No postwork but I'm trying to get volume and surface caustics to work- I think I need to use a non-reflective ground plane so we can see the light pattern of the rays that have passed through the shape.