Hi Peggy - Cute quilt. My guess is that the link originally went to an outside page that is now gone. The quilt as Barb said is made of two blocks. The Pinwheel Block is a square in a square in a square. The inner Square being the pinwheel. Here is a great resource for doing squares in a square.
http://quiltersparadiseesc.com/Calcu...Calculator.php
The link to the quilt said the finished blocks were 8" - plugging that in to that calculator gives you 5 5/8 for the larger inside square as a finished size. Then if you plug 5 5/8" back into the calculator you get 4" for the center square (which is your pinwheel). A 4" finished pinwheel is made up from 4 - 2" finished Half Square Triangles The other block consists of 16 half square triangles which finish up at 2" each (2.5" raw edge to raw edge)