Office Chair Wheel Stopper (Markus)

I started running sim racing games and I needed a brake for the wheels because I kept rolling away when pressing the brake.

After studying the current alternatives, most of which require lifting the wheel, I decided to design my version, which is a wedge that is inserted from the rear of the wheel. 

The cord is optional (I've used an old shoe lace), and it's used to remove the stopper more easily.

Print 2 copies, one breake for each side.