Previously, previously, previously.
Hmm, from the same planet as those clever round collapsing dining tables? Ron Resch would be pleased.
These appear to sacrifice some of the utility of leaving a door open just a crack and to raise the danger level of passing through a partially open door.
My first thought was about the opportunities that door provides for pinching an appendage. The glass version looks like it might shear effectively, as well.
It's a trap.