Electric Motor to Motor, can they self run?

There is a idea floating around the internet about self running two motors that are connected together. This is just a Demo of two 12v Dc PM electric motors connected together with a small flywheel between them, the idea on the net is one motor acts as a drive motor and the other as a generator when spun up the claims are the two motors can run each other like a closed loop can this work? This video is just a basic experiment and explanation, I don't go into detail and there are many factors involved.

I have a small flywheel in the middle of the two motors to address kinetic energy, I know it's not balanced very well and it's crudely built. This is just a simple experiment good for a kids science fair project can show motor to generator AC to DC current, etc.

This is only low voltage.

Don't forget about the laws of Physics, conservation of energy -Energy can be neither created nor destroyed but can only change form.