I belong to the Art Quilt small group of Kalamazoo Log Cabin Quilters. We meet monthly and work on a challenge inbetween meetings. In July 2013, it was a Circle challenge and exchange.
The rules were: for each set, to begin with a 11″ square, make four concentric circles (3″, 5″, 7″, 9″), cut your squares into quarters and ready to trade. For every square you make, you trade 3 quarters and keep one of the original quarters.
The most difficult part was slicing them into quarters! (Emotionally, not technically!)