The really bad invention
An assault rifle that automatically uploads a point of view version of its shooting sprees to You Tube.
* If you are in the military, this no doubt leads to critical security breaches and potentially tips off your enemies.
* If you are 98% of people in law enforcement, you don't need an assault rifle.
* If you are a crazed mass shooter, we don't really want to encourage you or make your job easier, and from a purely economic perspective, the market made up of affluent crazed mass shooters (these cost $7,500+ each) is not a really big one.
The good idea
Buildings in places where it snows tend not to be flat for good reason. You want gravity to cause snowfalls to slide off the roof.
But, motor vehicles of almost every shape and size have roofs that are very nearly flat on the left to right axis of the vehicle. Yet, most models of motor vehicles are sold in places where it snows sometimes and cars are parked outside sometimes.
Why not design car roofs so that they naturally allow snow to fall off to either side of the vehicle?
Now, you probably need a different shape than a building roof because motor vehicles are routinely exposed to much higher winds and aren't so firmly attached to the ground. You don't, for example, want a concave curve on each side of the vehicle into a thin, tall dorsal fin running down the middle of your car, which could blow you out of your lane in high winds.
But, a car whose top half of the chassis was in the smooth convex shape of half a jelly bean, or half an egg, or half of a rugby ball, would allow snow that fell on the roof of the vehicle to slide off much more readily to the sides of the vehicle, without impairing the ability to stay in a lane or navigate.