-You get two sheets of polaroid.
-Rotate one of the polaroids or the sunglasses.
-Supply your own sunglasses.
-Show the stress lines in plastic using polarized light.
-Put one of the plastic shapes in the metal frame.
-Place on the overhead between polaroid sheets and squeeze.
-Rotate one sheet to find the best contrast for seeing the stress lines.
-Place the card with "cellophane art" between crossed polaroids on the overhead.
-Rotating the art will produce stunning color changes.
-The "card" is covered with cellocphane tape.