Here's my freehand practice. I spent some time on Google looking for patterns I liked. I'm working with a modified version of one of the ones I found. I'd include my target image, except it most likely belongs to somebody who may or may not appreciate me re-broadcasting their work.
I think I will end up going with the green squares with yellow borders. I'm having a tough time getting the squares to come out nice and even and straight, so I'll practice more before I put it on the robe.