Here is a link to one that I did.
http://www.quiltingboard.com/picture...t-t134673.html
If you have not made a pinwheel, here is a link to great directions.
http://www.valeriecustomquilting.com...tPinwheels.pdf
I always make mine a bit over sized and trim down as that link suggests. They can be any size you want. If you want a
finished pinwheel of lets say 6 inches then each section of the pinwheel (which is called a half square triangle) would finish up at 3 inches square. You would start with two sets of two 4 inch square pieces of fabric (one is the background and the other would be the color of the pinwheel). Once sewn, cut apart and reassembled these four pieces of fabric would make one pinwheel.