First Mindstorms robot. Here it is in action:
I started out with the tribot, which has building instructions but no real
programs. I had to rip up the front of it to move the light sensor further from
the floor -- in its initial position it couldn't tell the difference between
white and black.
You can show the current readings of the sensors on the device, which would be
handy when programming thresholds, but they don't seem to match up at all... so
it needed quite a bit of tweaking.
Here's the source code:
Lots of room for improvement...