I like 6 1/2 sqaures that way I can cut them down for hexagons, fussy cut or use them in a square in a square like Anita Grossman Soloman has in her book rotary cutting revolution.
http://www.quiltingboard.com/t-103058-1.htm
I did not have enough variety to make a true I Spy quilt but I am collecting for one.
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