Just cut t-shirts about 12 1/2 " and iron lightweight fusible webbing to the back to stabilize the t shirt fabric. Add sashing or borders or whatever you want. I used a piece of prewashed and dried flannel for the middle layer and tied it at the four corners of each block. It is easier if all the t-shirt blocks are the same size. If not, add a border around it so that each block is the same size before continuing. I just finished one for my son using all his cross country and track t shirts from high school.