Metamorpho spots

What a fun (children) trick can be ...

The magician has listed a glance at the table, the look is black with white dots. He shows that the can is empty.
Then he picks up a white cloth painted black (black cloth) and a black cloth which is painted white (white screen).
He stops both in the can, make a magic move and takes the canvases again, while he says the white-painted cloth is now black and vice versa. For spectators there's apparently nothing so happens that will react faint.
Possibly you can do this of course again ...

Then you do the canvases again and say, now we do some dots on. You now get a visual of the dots of the can (!!) and throws it in the can.
Finally, you get a white screen with black dots and a black cloth with white polka dots from the tin.

Make it a fun story and you have a winner that provides a lot of interaction with the kids!