I recently purchased the Transparent Tarot, a deck which is printed on transparent sheets of plastic. Its images are designed so that a person can stack cards of a reading one atop the other and glean additional levels of meaning from a given reading.
Well, I've tried some "stack the cards atop one another" readings, and WOW. What a boost of insight comes from having a new way to interpret the cards! I keep thinking of the game referenced in Star Trek, 3-Dimensional Chess, because taking a 3-card reading and stacking the cards gives a 3-dimensional card spread.
I can tell that the mental workout I'll be receiving as I practice new reading techniques will serve me in good stead when I work with my more conventional paper decks.
What a fascinating learning experience this is turning out to be. :)