Hello,

I wonder whether someone is aware of published work where the principle from "Octal Pencil" (published in Fulves: "Curioser", p. 29+ and in Minch's "The Collected Works of Alex Elmsley", Vol. 2, p. 93+) has been applied.

So far, I have found an application only in Phil Goldstein's "Octaliar" (Magigram, vol 14, no 12, p. 758) and in two recently published articles in the German magazine "Magische Welt".

In technical terms, "Octal Pencil" uses self-correcting code where the Hamming distance between two words makes sure that it can be detected if the spectator lies (i.e. announces a "bit" wrongly) - but do not be afraid: In fact, one does not have to study mathematical coding theory to perform the trick.

It is said: Terri Rogers "Mug Shots",in which a book of criminal's faces is used.
(I don't own the trick.)

Thank you very much for mentioning "Mug Shots". I found a description of this item as follows:

"From a small book containing line pictures of shady characters, or Mug Shots, a spectator selects one,
then in answer to questions may lie as much as he or she chooses. Despite this the performer names the page, position and name of the chosen criminal! There are 76 characters from which to choose..."

I have to admit that I am confused by the phrase "as much as he or she chooses". Something says me that in fact there must be certain restrictions.