I'm not really noticing any banding, you seem to have stumbled upon anti-aliasing practices here actually. It makes the edge of your cube seem much smoother at it's default size, which is always a good thing!
There WAS some cutoff on the binary at the bottom though, which I've repaired here:
Also, if you want an idea on how to make it more visually arresting, the cutoff on the binary along the front-facing edge of the cube could be used to start a partial wrap and have it sort of "fade off" around midway. I can do an example of that, if you like.