It looks like this one, but with fewer pieces ...
http://quilting.about.com/od/anniver...pler_three.htm
If you stand on your head and close one eye <g> seriously .... the part that has the sawtooth around it is the solid half in your quilt.
The part that has all those HST, in your quilt is actually only one HST, with a Half square on the bottom part ... I wish I could draw better ... I will just keep looking for a few minutes ...