This is a concept design of a perpetual motion machine. A perpetual motion machine is a mechanical system that is able to move without a source of energy, without ever stopping, some designs are too bold to even claim that the system generates free energy (free energy machine).
Of course this design is not a functioning Perpetual Motion Machine, it is nearly impossible to design such system, energy is always lost while it makes its cycle in the system. It is lost in form of friction, heat dissipation and by moving the surrounding air which absorbs the energy.
Here is a brief explanation of how this simple machine could operate. An individual corn kernel falls on the heated platform (colored in red), the water in the corn kernel heats up and eventually causes an explosion (The POP), the explosion allows the corn to expand into a popcorn and this expansion pushes the piston downward and the Popcorn with it. At the bottom, the Popcorn exits the piston from the right side. The motion of the piston drives a gear which rotates a shaft connected to an electric alternator. The alternator generates electricity which is fed back to the heating platform.
By this design, the energy of the exploding Popcorn is partially recovered and sent back to heat up another corn.
I should point out however that this system can be multiplied to several pistons connected to the same shaft and flywheel , each allowed to input energy to the alternator freely but also keeping a more continuous motion for the flywheel. The gear and the flywheel are not connected by a straight shaft, the gear drives the main shaft by a torque in one direction and free rotation in the other direction, exactly like the drive gear of a bicycle.
There are few mechanisms removed from these pictures.There is a mechanically connected gate , that allows one corn kernel to fall into the piston when the piston moves downward and returns to place, this gate will allow feeding in the kernels, one by one. This system also assumes that all corn kernels will explode. It is of course possible to later add electronic smart systems that detect a bad corn kernel and disposes of it to keep the Perpetual popcorn machine running.
Of course a system like this has no point other than interesting mechanical design , popcorn making and just a fun thing to try out. All previously design “Perpetual Motion Machines” had no purpose, at least this one , while consuming energy from the electric grid to keep running, it will also make you something to munch on while you watch a movie.
There could be in fact a perpetual motion machine, if you can cheat with the conditions, for example, two bodies in the vacuum of space connected together by gravity, can rotate around each other endlessly if there are no external gravity fields affecting their motion and no contact between the two bodies to create friction.