All the components make their electrical connections and mechanical connections through a common snap like you might find on clothing. Of course, with the snaps, that’s not very hard, but [Chuck Hellebuyck] got creative with TinkerCad and worked out how to 3D print custom modules for the system. The system uses 12mm snaps, and although [Chuck] doesn’t do it, you could probably 3D print your own baseboard, too, and not use any original Snap Circuit equipment if you wanted to do so.