whenever I plan a block, or am not sure if things are going together correctly, I grab some graph paper... the math is so basic and it does take the frustration down and out!! You have to remember to take your seam allowances into account. If your 3 large blocks are 12 3/4" - is that "unfinished?" This is important because if it is, you need another 1/2" background/sashing than if it will be 12 3/4" after you sew it to the sashing. so... STEP 1: measure everything you have as it would be "finished" say 12 1/4". STEP 2: tape 2-3 pieces of graph paper together and have each square equal an inch - mark off the desired width of your row... STEP 3: cut "model squares" your large squares will be 12 squares and a fourth of the 13th square. If you want, cut three of these out - and also cut two graph paper squares the model "size" of your smaller blocks. now place then on your blank graph paper "row". You will be able to tell if the 5 squares you have will work out simply with sashing or if you need something more. Don't feel you have to make 5 squares the same size... different sizes add interest. [I hope I havent confused you :roll: ]