A large domino is removed from a vinyl holder. The spots are magnetic and can be freely moved. You claim lots of people think that magic is done with mirrors. As you say this you remove a small mirror from within the holder. The spectator is asked to move the spots and make any domino they like. NO FORCE, no wording etc they move the spots anyway they like.
Let's assume they make a 4-2 domino. You say you had a prediction made before they chose their domino. I will prove that magicians use mirrors for their tricks. You stand the mirror in front of the domino saying look in the mirror and you will see my prediction.
This always gets a laugh or a groan. They are looking at a reflection of the 4-2 they made. Ok, but I did make a prediction. They turn over the domino and on the other side PRINTED is a 4-2 domino.
Sounds impossible but true, Fits into your pocket, no reset spot on is always SPOT ON.
Easy to do, works every time. Comes with an instructional DVD.