Capicua

Always win at the "heads or tails" game, even with borrowed coins.

Imagine being able to always win at "heads or tails," with any coin. Capicua is a new, intelligent, and practical technique developed by Manuel Leal and produced by Thinking Paradox. The effect is as follows: you borrow a coin from a spectator and spin it on the table. The spectator can stop the coin whenever they want, yet you will always know the final result.

You can present it as a mind-reading effect, an impossible prediction, or simply as a curious skill. The best part is that the method is so practical that this will be one of those effects you can perform whenever someone asks you to show a magic trick, even if you have nothing on you.