How to draw Islamic geometric patterns

Over at the Root Simple website, Mr. Homegrown wrote about the fun he's been having learning how to draw Islamic geometric patterns from this book by Eric Broug.

It's a book of step by step drawing instructions. All you need is a ruler, compass, pencil and pen. While the geometry behind theses patterns is enormously sophisticated, actually drawing out the shapes is surprisingly easy and relaxing. It's also a fun and painless lesson in geometry, especially for those of us not inclined towards math..