Wheel stand

I live in a relatively small apartment and needed some way to store my new esk8 Propel Endeavor 2GT with 8" tires. I chose to lean the esk8 against the wall in a vertical position as the best and most convenient option. However, in this position, there is a risk that due to inattention I will lean the esk8 at the wrong angle and it will run under the wheels and fall off.
So I decided to design a chock under the wheels that would ensure that the esk8 would not move in any position, not on any surface I leave it leaning against a wall or when I'm on a trip somewhere and stop on a hill and don't want the esk8 to roll off.