This is a very magical and ingenious way of revealing a selected card - it maintains the audience's interest throughout, building suspense until the final reveal. They will love this! You surprise and entertain your audience at the same time - what could be better?
The magician displays a pack of cards having different pictures on their faces (e.g., ball, car, glove, etc.). The spectator cuts the cards wherever they like, and a card is selected at that exact position. The card is shown to the whole audience. The magician points to a block which has been sitting on the table since the beginning of this routine. He explains that this block can guess which card was selected. As the magician magically moves the block's pieces into various positions, it displays a message with each manipulation. Its final image is identical to that of the spectator's selected card!
ABC Block Prediction is fun to perform, and will stun your audience!