ARM has posted a video to their YouTube Channel showing a Nokia N95, coupled with LEGO Mindstorm NXT kit and LEGO Technic pieces, solving a 4x4x4 Rubik's cube. The N95's camera is used to identify the layout of the colour squares and work out the moves necessary to solve the puzzle. The N95 then instructs the LEGO model on the moves to make.
"Possibly the first ever 4x4x4 LEGO Rubik's Cube solver? This Rubik's Cube solver was designed and programmed using a Nokia N95 mobile phone, a LEGO Mindstorms NXT and lots of LEGO technic pieces."
The 4x4x4 Rubik's cube is significantly more difficult to solve than the standard 3x3 cube.