The Old Maids Puzzle quilt block as shown in this layout is set on a 3 by 3 grid and uses a square and half square triangles units. This block is very simple and flexible in the different sizes that it can be made into. Over at the myquiltgenie blog, it and other variations of this quilt block are used in a quick quilt project. A quick reference is also available for 4 different block sizes.
I find it funny, the large number of blocks that are “puzzle” blocks or “choice” blocks. Some day I think I’ll have to find as many as I can of all the puzzle blocks and put them together in one big sampler quilt. I wonder how big it would be. Ah, inspiration for yet another quilt project.