Yes, the two auctions of embroidered and unembroidered blocks do match. Yes, 5 blocks that measure 18" x 18". After squaring off and being sewn probably 17" square. 17" x 3 = 51". I believe the top of a full size mattress may be 54" W. I would use lattice work to make the quilt the size I wanted to. Or, use a solid or print alternate 17" square. You could also make a 25 patch block as an alternate block and make a very large quilt using both auctions. Lots of possibilities!