You want a person to get a crystal ball. You said to him: I will draw lots for you. 1 No.is XX (object), No.2 is XX (object), No.3 ... No.5 is a crystal ball.
If you say so, you can take five brands (not necessarily five, it's up to you) and write "5" on them, so that no matter how he touches them, he will always touch 5.