Venti-llusion by Gregory Wilson & David Gripenwaldt

“I love this trick.” -Gregory Wilson

You show two cups exactly the same size with exactly the same amount of coffee in them. With one cup in each hand, you hold them at chest level, showing that if you extend your arms in opposite directions it appears that one cup is larger than the other.

You end by making the impossible happen in that one of the cups is now clearly larger than the other — with illusion becoming reality!