it's actually pretty easy when broken down into component parts. Take the block you want to enlarge, and figure by how much. If you want to double it, take each piece, remove the seam allowance, resize it to twice the size (say, from 2" to 4") then re-add the 1/4 inch seam allowance all around. Or you can simply photocopy it at 200% then add the seam allowance. And I always said, if they had taught me math through quilting, it would have been a snap--geometry, algebra and trig all are useful quilting knowledge!