OCI (Orthogonal Cylinder Intersection)

This is mostly just an 'interesting shape' thing.

Background:
- A 2D projection of a sphere appears to be a circle, no matter the orientation of the sphere.
- A 2D projection of a cylinder appears to be a circle, as long as you're looking down the axis of the cylinder.
- If you intersect three orthogonal cylinders, you get an object that appears circular along each cylinder axis, but it is NOT a sphere.

To make:
- Print two copies of the .STL.
- Stick them together (paying attention to lining up the 'edges').