This is the first version of my Babushka bot. I am currently working on MK.2 and should be posting it in a few weeks. The name comes from the traditional Russian dolls where one nests inside another of similar or identical design.
The idea came rather suddenly when I realized that I have two battery boxes, receivers, and two of each kind of motor, making it possible to have two robots made simultaneously. And having one ride inside another just seemed pretty cool.
I started by building the smaller one and pretty much just built the "carrier" around it, starting with the tray that it rides on. It took awhile, but I eventually figured out a way to place the motors that was stable enough that they wouldn't tear themselves off due to the combined weight of the two robots.
It's not really very practical, because the smaller one can handle more diverse terrain more quickly than the "carrier." I'm thinking of it more as a proof of concept, and I hope that MK.2 will prove to be more useful.