Old Windmill quilt block

I've just finished the latest quilt block calculator - Old Windmill - which is entirely half square triangle units. You have the option of making the units with squares or using a right triangle ruler to cut them from strips. Once I learned how to use the right triangle rulers, I was hooked. You no longer have to figure out the weird seam allowances - just add 1/2 inch, cut a strip and cut out triangles.