Oh what a great scrappy quilt that would be!! And would show those two echo-designs even better in a larger finished quilt than the mini in that Pinterest pic.
Sorry, I can't give you a pattern name or pattern ... but I can tell you how to make it. Just hope that my crude explanation makes sense to you ... others may have a more eloquent explanation!!
Make a boxed square ... then put a plain piece of fabric on top, the same size ... stitch diagonally, and cut to make two-HSTs. You'll now have two matching HSTs. Add sashing and cornerstone to two sides. Blocks are done and then you can play with them on your design wall, to ensure same colours do not touch.
As for measurements, I'd probably draw it up on graph paper for the size you think you want. Then do a trial run to decide if you have the centre square big/small enough for your liking. It's a design that'd work well either in smaller delicate blocks if you like small work. Or if you want larger sized work, would be great too.
Have FUN! ... and look forward to seeing what you make!