Three separate empty clear tumblers are shown. You stack all three on top of one another.
You have three smaller cups or bottles of soda with different colored liquids (not supplied) , say Purple, Yellow & Orange. You ask the audience what color liquid to they would like to start with. You tell them you will pour it into the tumbler of their choice (top, middle or bottom). Let’s say they say orange in the bottom one. You pour orange into the top tumbler and the liquid passes through the top tumbler and fills the bottom tumbler.
Once filled, you then ask which of the remaining colors to use and which tumbler to fill. Let’s say yellow and in the middle one. You pour yellow into the top and it passes through the top to the middle tumbler. You take the final purple liquid and pour into the top tumbler.
All the cups are unstacked and poured out to prove the liquids are real. Includes 3 special tumblers. You supply water and 3 cups or bottles of colored drink.