Participant holds a small blank piece of paper sandwiched between her hands and thinks of a word. You begin to talk about time travel and how you discovered that it's possible to travel back in time in your mind.
Performer instructs her to travel 1 year back in time in her mind. In the past, she must find you and tell you the word she thought of and she must also tell you to write this word down on a small piece of paper. (All of this takes place without her speaking a word in the present.) Then, when you both shall meet again 1 year into the future you are to give her this piece of paper as part of a time travel experiment.
In the present again, you tell her you must know the word because she told you 1 year ago ... you of course know and immediately tell her! She then lifts up her hand and written on the once blank small piece of paper is the word she told you 1 year ago in the past! She has successfully altered the present by going back in time in her mind!