This is a bottle. But not just any bottle, a special bottle. This bottle has no top or bottom, nor a front or back, nor even an inside or outside. This special bottle is called a klein bottle.
Klein bottles are non-orientable objects, meaning they have no definable sides. The outside flows to the inside and back again, making it impossible to discern between the two.
Of course, this isn't a real klein bottle. It would be physically impossible to create a real klein bottle. Like my mobius strip-based models, this is the closest possible 3-dimensional representation of the object. Still, it's mathematical and theoretical properties are evident and fascinating.