> Somewhere along the line we had a robot that I don't think is made any more, but it had a paper disk with two channels of information for driving the two whee

> Somewhere along the line we had a robot that I don't think is made any more, but it had a paper disk with two channels of information for driving the two wheel motors, and you programmed it with a black crayon. Sounds like one of the old OWI MOVIT robots - they used to sell a version (I think it is discontinued but still available from some vendors) called the "Binary Player Robot Kit". It doesn't look the same as the original version in the 1980s, but the internal circuitry is probably identical.