You can get by with one ruler with angles showing on it, although two is easier. In addition to that, I bought Kaye Wood's Starmaker 5, 6, and 8. The 6 is an equilateral triangle (60 degree triangle). The 8 is a right angle triangle (45/90 degree). Those two (not necessarily the same brand, but something with those angles) are fairly essential. I bought the 5 because I'm facinated with 5 pointed stars.