To 'stack and whack' we were taught to take a grouping of however many you want to stack. Let's say you have 6 different square fabrics. We cut ours all the same size to begin with. I had about a 10" square. You stack them neatly on top of each other. Then cut...(whatever angle or direction you want)put the top right piece under the right side stack. Sew them all back together. (Now they don't match fabrics) and, you continue this process 6 different times (because of 6 layers) Each time taking the right fabric once cut on top, and put on the bottom right side stack. How much fabric it takes could be however big you want your quilt. This is a fun project and the bright batik's look super this way. Skeat