It is funny you should ask about 4" squares. I just gave a class at our local Senior Center on sewing curves. We decided to do a scrappy DRUNKARDS PATH. We settled on a 3" drunkards path patch. While organizing the specifics of the class I discovered I could cut out both template shapes from - you quessed it- a 4" square. You need a dark and a light shade in each patch so - there you go. I will cut half my patches with dark and half from light. Exchange the "pie piece" light with dark etc. Sew together, square up to 3 1/2" and proceed to arrange the blocks in what ever pattern I choose.
I took a Bonnie Hunter class last fall. Decided to organize my stash ala Bonnie's Way. A 4" patch was one of the sizes she cuts her blocks in, so I had a "bucket of 4" blocks" already cut and waiting. Have fun!!!!