The Genii Forum

My brain is an omelet. Scrambled.

Here is a presentation by Max Maven on The Gilbreath Principle from the latest Gathering 4 Gardner conference.

https://www.youtube.com/watch?v=ht_2ai4N9BY

Thanks for sharing thisclip

After you watch the Max Maven piece, click on "Gathering for Gardner" below the video to go to their page of youtube videos. There are many talks from not only the 12th conference in 2016, but also the 11th in 2014 (including one of some doofus talking about Theodore Deland).

Ones of possible interest to this forum include Jason England on cheating devices, Adam Rubin on his most recent book, Alex Bellos on elliptical pool tables, Gabe Fajuri on things he sells at auction, Dana Richards on the things Martin Gardner wrote as a juvenile, and things he wrote as an adult for juveniles, Charles Sonenshein on a Milbourne Christopher rope trick, Lennart Green on magic squares, and Gary Foshee's harmonic pendulum.

It was great seeing your talk on Theo Deland, Bill!

https://www.youtube.com/watch?v=wzK9dCO_tr4

I really hope the book comes out some time this year.

I have spoken a lot about The Gilbreath Principle in this thread.

Well - here is an important update. Tomas Blomberg has extended this principle with an idea called Interlocked Gilbreath. You can find it in his book called Blomberg Laboratories. It is a great book and his work on this principle is pretty special. He has pushed it further than anyone else I have seen.

Bill, Enjoyed your talk on Deland.
You look different than what I had imagined.
For some reason, when reading your posts, I have always envisioned you as looking like Ed Asner ...

I'm not quite sure how to take that . . .
(but I do hate spunk)


When I was younger, I used to get accused of looking like Ernie from "My Three Sons". Now, occasionally (and I don't get this and can't figure out why) people will tell me I look like Stephen King. In the past 5 years, I've had 3 or 4 random strangers walk up to me and tell me that.

Some more videos have just been added. They include some short ones featuring impromptu tricks from Gardner's Encyclopedia by Mark Mitton, Dan Garrett, and Martin Gardner's son James.

(and speaking of Ed Asner, he has come up on the forum before)

I guess we all know that if a deck of cards is riffle shuffled into another deck of cards (that is in reverse order) - and the combined deck of 104 cards is cut exactly in half - you are left with two decks of 52 different playing cards.

It was one of the first (and still most interesting) uses for The Gilbreath Principle. In the example above - both decks have the same coloured backs.

Well - it is worth checking out 'Out Of This Neighborhood' by Norman Gilbreath. It is on page 740 of the May, 1989 issue of GENII magazine (Dai Vernon is on the cover).

In this trick - Norman extends the idea so that you can do the trick with two decks of different coloured backs. So after they are riffle shuffled together - you show you have two decks of 52 different cards. Each deck having a different coloured back. It is a fascinating problem although it is a bit of a pain to set up. And probably only of interest to magicians.

Still - it is a fun little trick to play with for those interested in this principle.

If you like that, here are a few related ideas (not necessarily using Gilbreath). Most of them a bit undeveloped:

https://www.conjuringarchive.com/list/b ... ight=35318
https://www.conjuringarchive.com/list/b ... ight=68118
https://www.conjuringarchive.com/list/b ... ight=38888

Thank you for all the detailed information, Joe. To contribute to 1), there is "Blindsight", by Nick Trost (The Card Magic of Nick Trost), and the one-deck version by Bob Neale, "Probability Pack", in Life and Death and Other Card Tricks. Also, it seems 4) and 9) use the same wonderful idea, no?

Joe Mckay wrote:5) A nice idea (not mine) to set up for Gilbreath effects is the following:

1) Have a deck shuffled - or use a borrowed shuffled deck.

2) Run through the cards and say that you need to remove some cards at random.

3) As you go through the cards, you throw out all the red and black cards which interrupt the red/black pattern running through the deck. So - you are basically throwing out the cards which are not already in red/black order.

4) You will be left with a pile of cards - face up on the table. They will be in a mixed up order and this helps make everything seem fair.

5) The pile that is left in your hands is now (secretly) in red/black/red/black/red/black/red/black etc order.

Juan Tamariz credits this idea to Alex Elmsley. Does anyone know where Alex published it?

Here is an unusual Gilbreath principle trick. It is from an academic journal that set itself the task of using a computer system to aid in the design of a new magic trick.

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0181877