My students often ask me at the beginning of the lesson, if they can draw a card. I especially use the cards for memorizing passages or getting ready for a concert. I use very short passages for the little kids, repeating them using the cards. As the student first focusses on playing/learning a passage, then on drawing a card and again on playing the piece he/she has to actively remember the passage, and the piece is repeated without the student noticing. By using different characters and techniques early on the student develops a large pallet of means of expression.