There is a common belief that many magic tricks are "done with mirrors". Well, this one really IS done with a mirror!
Show your spectator a little flat domino shape, with six magnetic dots. Let him make a domino, putting some of the dots on one side and some on the other.
When he's finished, tell him you've made a prediction about what design he was going to make. Your prediction can be seen in the mirror- well, of course it's right!
Just when he thinks it's all a joke, show him your REAL prediction- a picture of the EXACT two number domino he designed!
This wonderful trick is EXTREMELY easy to do- in fact, you don't need to do anything but the talking! It works itself!