Jo Belmont

This is a perfect spot to use a couple flat mirrors. Imagine that two square mirrors are joined by a hinge. Place that "hinged" joint a the corner of the block to get a quick idea of what the block's going to look like when joined together. Also a really quick way to get an idea of changing up the joining of the blocks (simply relocate the mirrors to another corner). This works well when you don't have the fabric, time, want to make more of potential blocks.

Edited to add: By the way, I really love the block the way you have shown it. I believe when put together, it will have a subdued, but very elegant look.