Effect: Ed Massey’s Duplex Slate was the first slate to produce a message on both sides. A slate is shown and both sides are cleaned with a damp sponge.  It is then wrapped in a piece of paper and immediately given to a spectator to hold. The person holding the slate is asked to unwrap the paper himself and writing in chalk is found on both sides.

Points to remember:

• Slates is cleanly shown on both sides
• Nothing is added or taken away from the slate
• Slate maybe handled by the audience before and after