Secret messages: Show the children how to send secret messages. Simply draw something with a light blue pencil – and then draw red circles over it, and the message is gone already. Now the information can only be decoded by using the red plexiglass screen.
Counting: Encourage the children to count certain things: How many people does the puzzle show? How many different objects did the thief steal? How many police officers do the children find? And how many balloons are used as decoration at the birthday party?