What is really happening? The square spins and the pictures change so fast the your brain cannot discern them and accepts them as one thing. That’s why we see one picture – the princess is kissing the frog.
Here is the template for you to print. You need: a square piece of cardboard paper to place between the two pictures and some thread.
- Cut the template.
- Colour the pictures.
- Fold by the template in the middle and insert the cardboard between the two pictures.
- If you want you may stick the template onto the cardboard, but it is not necessary.
- Make two holes, using a sharp object, on each side of the cardboard.
- Insert two pieces of thread (each some 50 cm long) through the holes and fasten as shown on the picture. Tie the ends of each thread.
- Hold the nods and leave the cardboard hanging loose. Start spinning it until the thread is twisted.
- Stretch your hands. This will make the cardboard spin very fast.
What can you see while it is spinning?