It's that final category that today's weird filing comes from. Ford, it seems, is toying with the idea allowing drivers to remove the rear wheel of a passenger car so that it can be used as a sort of oversized unicycle. We think it'd be a better bet as a sort of modern-day penny-farthing.
The filing was made in June and only published last week, according to Patent Yogi, and describes "a self-propelled unicycle" that is "selectively disengaged with the vehicle for independent use." Power comes from an electric motor attached to the unicycle's single hub.
It all seems very silly, but as urban areas become increasingly congested, the idea of using your car as a sort of mothership for a small, zero-emission runabout doesn't sound like a terrible idea.