Hey, I got a better idea than this. How about this. A small card is introduced. On it is a QR code. The spectator is asked to think of any object/animal/thing in the world. The the spectator is to use the own phone to scan the QR code. The code will link to this website. There they have to answer just 20 simple questions about the thing they are thinking of.
And instead of charging 31,50 dollars for it, I'd sell it for 30. It's a bargain. And not overly complicated at all,