Islamic Geometric Patterns
Some Moslems believe that sacred art should not reflect nature, because nature is God’s work and cannot be improved upon. They let much of their sacred art be inspired by geometric patterns. While not all Islamic sacred art is geometric, there is plenty that is.
There are many photos and tilings of Islamic Geometric Art on the Internet. One site is PatternInIslamicArt.com and another is Wikipedia.com/wiki/Islamic_geometric_patterns.
These patterns are excellent examples of things that can be created with Turtle Graphics as they are generally created with a compass and straight edge.