1. Pick a card and think of your favorite 4-letter word, such as DODO or FART.
2. Using the wooden handle, position your card underneath the first letter of your word, and press the red button. Only touch the handle so that you don't make it obvious which of the 26 card/letter combinations you have picked.
3. After the cards are reshuffled, use the handle to move your card under the second letter of your word and press the button again.
4. Repeat for the 3rd and 4th letters.
With the shuffling, there are 26 × 26 × 26 × 26 or
MINDPOWER is based on an effect by bob hummer as related by martin gardner & karl fulves.
special thanks to david britland for suggesting the idea & consultation.