When Greathouse thinks up a project, whether it's an electric wheelchair with faux machine guns or a talking remote-control robot with a skeleton's head and torso, he doesn't start with sketches or computer-aided design. He dives right into fabrication. For the tailgate rig, he started by gathering the parts: a used grill from Craigslist, an inexpensive wine refrigerator, a discarded flat-screen monitor, an electric wheelchair, and a whole mess of steel tubing and steel plates. Once he imagined how it could all come together, he built a frame out of steel. He set the wheelchair's driving wheels at one end and freely spinning wheels at the other and fit a joystick that drives the rig into a recessed panel above the fridge.