4 level might be nice, but the problem is that in the first demo it ran at about 8-12 FPS, and the grayscale already suffered from it (for decent grayscale, it has to be refreshed about 25 times a second at regular intervals), so I think 4 level would look too flickery, unless you ran DispGraph^rr commands 3 times in a row or something in the same fashion as in Reuben Quest.