Oh man, I was just reminded of the Real Robots magazine series, and that's a bit of a throwback
For context, this was a magazine series where a new issue came out every 14 days, and each issue included a component of a robot; you'd end up building it over time. It could be controlled manually, or follow lines / detect obstacles.
Horrendously expensive in the end, but very very cool nevertheless.
This is a pretty good video on it! It also shows how it works
https://www.youtube.com/watch?v=z6ht9M07ALU
Neat, apparently people have been modding these things: https://community.element14.com/members-area/personalblogs/b/blog/posts/arduino-rejuvenates-an-elderly-real-robots-eaglemoss-publications-cybot---part-1