I made these two small pincushions for 2 very special people. The blocks are 4 inches square.
The third dimension is created by sewing the tops to a back that is exactly the same size but is rotated 45 degrees. This means you are sewing the corner of a square to the middle of the other square. I love the depth this creates.
I stuff them with leftover wool batting which gives them shape and also is a great filler to stick pins in. These were the smallest ones I have made and I have to admit it is easier to make larger ones!