Of course there is no such thing like working perpetuum mobile. In these project I would like to show my kid how to built something which looks like perpetuum mobile because it can work without any visible force but... in real it works because of heat energy.
What will be needed ?
Only paper page, the wire and some lamp.
Step 1: Spiral
Take the paper page and write the spiral on it. It could be made 'by hand'.
Then cut the spiral using scissors.
Step 2: The Holder and 'mechanism'
Take the wire, cut some and make a holder to hang the spiral over the light bulb.
The best lamp for that would be the lamp with triangular lampshades, because the heat in such lamps is concentrating at the top.
Step 3: Run Your Device
Now turn the lights on and wait... the spiral should be spinning.
Because the lightbulb is getting hotter and hotter as well as the air above it. The air is less dense so it goes up and moves the spiral.
All will look like spiral is moving without any force, by itself, but when You turn the light off it wil stop to move.