I measured a simple "Pull Back" style motor that I found in a dollar-store toy, and recreated the "Cat on a Vacuum" meme that you see on YouTube videos with this toy. The design of the robotic sweeper was entirely by eyeball, and made just thick enough to hide the motor. No specific brand of automatic carpet cleaning device is expressed or implied, of course. Any resemblance to an actual trademarked product is just as coincidental as a company naming itself with a lowercase-i-capital-noun format (like Apple products) or naming itself after famous science fiction stories (like Asimov's books). For some reason, Slic3r 0.9.9 complains about it being non-manifold, but Blender cannot find any fault with the STL. The slicing results are perfect. I recommend the concentric top fill to complement the contours of the robot. This uses a cheap "Pull Back" style motor I scavenged from a dollar store toy kit. I used mechanical pencil erasers as tires, and melt-insert some metal bushings for the front axle. (The melt-insert threaded bushings are optional, but McMaster-Carr part 94180A331 is a bag of 100. Great for 3D printed projects!) A more complete picture gallery with helpful tips is at http://imgur.com/a/eD9cW If your pull back motor differs, you will obviously need to adjust the STL design of the model. However, I hope this project inspires many people to run to their local discount/dollar/100yen store and look for new ways to mashup common toys with uncommon ideas.