Here is a paper from a research group that tested if different shapes and colors help bees recognize their own hive in a grouping of hives.
I know this is a unique shape that they can see: 
My nucs are ready with these shapes/colors to help our bees: 
Cool! Nice find. Hopefully, I will get a chance to read that soon. I’ll probably find out that my red spray paint graffiti is not the best option.