You have three cardboard cylinder (blue, red, yellow). They included one in the other. Inside is a toy, for example, matryoshka. And cylinders, and the dolls have the same height.
Ask the audience: "In which of the cylinders you would like to see the doll?" Call, say, red. Place the cylinders separately. The toy was really in the red. If you collect the cylinders again and return the doll in place at the request of the audience it can again find yourself in any of these cylinders.
The secret is simple. In the head dolls made finger holes, which side is not visible. Raising the desired cylinder, insert into a secret hole in the index finger. When disassembling the cylinder hand should be on top.