I couldn't wait to test some of my ideas for how to simulate states between black and white on the NXT's display, so I did a quick test run by using the same on/off principle I already used for imitating polyphonic sound output. Thanks to the display slow reaction time it's possible to simulate different, slightly moving/flickering shades of grey by shortly display them every n milliseconds. I think I could get really smooth shades with some more experiments, but I don't think it's a good to invest in it. Those alternating black/white pixels require constant redrawing - even with only bitblit functions you can't do this quick enough for big screen areas. It's only suitable for small sprites due to it's slow reaction speed. But I could probably speed the rendering by not accessing the more far away graphics memory using setPixel, but using some of leJOS predefined buffer copy functions. Hm, could solve the problem and would speed up the drawing speed enormously. Hey, that's also interesting for the renderer. If the performance can't be improved, I'll rely on dithering.