Jack Shalom has discovered something very cool... a previously unpublished attribute of the Triskadequadra Principle that greatly simplifies its application and may open new doors. He has granted permission to release this, and I do so with sincere thanks and embarrassing giddiness!

Those familiar with the principle will understand:

There is no need to check post-shuffle to see whether you've obtained family #1 or family #2. Just monitor the pre-shuffle cut: If the suit of the bottom card of the top packet matches the top card of the deck, you get the “family” that has doubles of cards #2 and #4. Otherwise, the doubles will be of cards #1 and #3.

For example, with a deck in CHSD order (top to bottom, face-down): If the bottom of the top packet is a spade, your riffle shuffle generates family #1: CHSD, CCHD, SSHD. If the bottom of the top packet is a club, you get family #2: CHSD, HHCS, DDCS.

!!!