Reuleaux tetrahedron - Solid of "almost" constant width (OpenSCAD)

After watching Angus video, I got curious and decided to experiment with the concept of "solid of constant width".
https://youtu.be/2eUWT9cI23o

I implemented it based on a tetrahedron.

[Update 06/05/2017]: It turns out that this shape is called a Reuleaux tetrahedron, and it's NOT a shape of constant width. It has a slight extra width between 2 opposite edges. The popular solution to make it constant width is to implement the Meissner tetrahedra. The mathematician in me doesn't like that