Inspired by my trip to the MIT media lab last week, I wanted to show the boys how you could build an programmable interface via a very simple UI. So we built this Mindstorms crawler that was supposed to respond in unique ways to different pulses of light, in some cases going forward, on others turning, and in others still backing up.

As it turned out (as is usually the case with the NXT programming environment), programming the photocell module proved to be a lot less intuitive than I would have imagined.  But what was worse was that all Andrew wanted to do was shine the light straight on to get the robot to "follow" him around.

I guess in a way this is programming by light. At the very least it kept him entertained for the better part of an hour until he led his robot off of a flight of stairs.