Robinson Triangles
Robinson triangles, also known as golden triangles due to their close relation with the golden ratio discussed previously, make up the spikes of regular pentagrams.
A golden triangle is an isosceles triangle where a ratio between one of the identical sides $ a $ and the base $ b <math> is the golden ratio <math> \phi $.
Further Readings:
One final note – if you like proofs, you will enjoy this site: http://mrbertman.com/penroseTilings.html. It contains many definitions and theorems that deal with how to place a tile correctly (the site uses the term “legally”) and why those rules exist. You can even create your own Penrose tiling!