You can also find a bunch of pre-made geometric shapes on grabcad.com, like this one:
https://grabcad.com/library/basic-geometric-shapes-3d-1

Also check out this page which has a bunch of polyhedron objects in 3DM format that you can download and import into MoI:
http://www.rhino3d.nl/pythposter/pyth3dm-eng.html

- Michael