Fabric like wall paper as a repeat in the design. When you do stack and wack you need 8 repeats, and if you want to use your main fabric as a border you will need to buy additional. You use your ruler to cut your 8 repeats. After you cut your 8 repeats, you stack them, starting in the center, you pin the stack together, again using your ruler, you cut strips of fabric, then using a Kaliedoscope ruler you cut these strips into your wedges that you sew together, add triangles to 4 corners and you have your stack and wack blocks. There is a little more to it than this but you get the general idea. I have taught several classes on the stack and wack and they are alot of fun to make.