Here is a portion of a WiiWare World interview with MindWare about MaBoShi: The Three Shape Arcade on WiiWare:
"WiiWare World: How many levels does MaBoShi have? What sort of variation occurs as a player processes to the deeper levels?
Micky G. Albert: Each game will get harder towards Level 99. If you beat Level 99, you'll be back to Level 1. The challenge come from both the level design variety and enhanced enemies (they'll get faster as you progress, for example).
We wanted to make each Circle level distinct by its central primitive motif. This way, players can see "this level is different and new!" at a glance. It was challenging to assure the level design variety only using limited design elements. We hope players will feel "What comes next? I want to see it!" as they progress. Kuniaki Watanabe designed all levels.
We changed the whole level design several times. The biggest design decision was making each level drastically short to 1-3 screens long. We had some doubts at first. It's rare to see a scroller game with such short levels. But I think the change ended up well. We hope players can enjoy short yet intense Bar levels. I oversaw the game balance of the Bar game all by myself.
Square levels are procedurally generated. So each time you play, you would feel the levels look familiar, but they are not exactly the same. Jun Shimizu (He coded Slap Fight MD alone), Tadashi Ito (He coded the DS version of MaBoShi, as well as Bar/Square on Wii), and I wrote the generation codes. If only one coder do the generation code, the result might become monotonous. But if we have too many coders, the end result might become inconsistent. So we had three coders to make each level distinct yet consistent as a whole. We hope players will recognize each stage by their pattern not by their level number."