In this trick the mentalist places a sealed envelope and 3 different coins on a table. The participant picks one of the coins. The chosen coin is flipped to see if it lands heads or tails up.
The envelope is opened; and inside is a folded piece of paper. The participant opens the folded paper to read the prediction. The mentalist has not only predicted the chosen coin, but also whether it landed heads or tails up.
Much like a "Force" in card tricks... You will use the mentalist trick of "Magicians Choice" in this effect. Even though the participant thinks they are choosing a coin by their freewill; you are actually forcing them to choose the coin you want them to choose.
The other "trick" you will use in this performance is known as "Multiple Outs"... which is how you will "predict" whether the coin will land heads or tails up. To set up your multiple outs, you will need to prepare the envelope you are using to hold your prediction in a special manner to hold two "outs" (in this instance the 2 outs are "Heads" and "Tails").
To prepare your multiple outs you will need to make an altered or "gimmicked" envelope. You will require two identical envelopes... those small brown envelopes work great. Modify the second envelope as in the diagram on the right. After you have your gimmicked envelope all ready, you place a piece of folded paper in each "compartment" of the envelope. One that reads "You will choose the quarter Quarter - and it will land Heads up" and another with "You will choose the Quarter - and it will land Tails up". (if your foretold coin will be a quarter). Seal the envelope.
Now that you are all organized... on with the performance: