Plastic cover - Mirror image

This time, A just smeared blue and yellow paint on a plastic cover while observing that the combination of blue and yellow changed to green colour.

Later, she was asked to place a sheet of paper over the cover, press gently and remove it. Upon this, the mirror image of plastic cover is seen on paper.

You could stick various shapes on the cover before placing paper, there seems to be no limit to imagination.

This one may be the simplest version of this kind.