If you were a nerdy or creative kid, chances are you grew up playing with building sets. Certainly LEGO—Its robotics capabilities, like the three-dimensional (3D) scanner pictured in Figure 8.1, are well documented. Even beyond that, however, do you remember Erector, Meccano, K’nex? Folks have been using building sets to design robots since the beginning. Usually they use the motors and other electronics, if any, that come with the set, but the true power user mixes and matches. Do you like that Tamiya gearbox but want to use LEGO wheels? Someone’s already figured it out.