Did Dirac ever publish anything about his string trick?

Question

Paul Dirac often used scissors and strings to demonstrate the properties of spin 1/2 and of SU(2). The demonstration is variously called the "string trick" or the "belt trick" or the "scissor trick".

Did Dirac ever publish anything about it - in a paper or in one of his books on quantum theory?

Searching on Google scholar it seems that he didn't - but is this conclusion correct?

Comments

@Johanna , I am not sure if Dirac wrote about it; but you can find that in Roger Penrose's and Wolfgang Rindler's textbook called Spinors and space-time volume 1 on page 43.

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Online book is here: https://fr.scribd.com/doc/76806799/Roger-Penrose-and-Wolfgang-Rindler-Spinors-and-Space-Time-Volume-1-Two-spinor-calculus-and-relativistic-fields

Answer 1

P. Dirac's string trick does not and may not demonstrate the properties of spin 1/2 of SU(2), as a matter of fact. First, SU(2) transformations are not real rotations, but recalculation rules from one still reference frame to another one. Second, his trick works for real rotations whereas a rotation to $2\pi$ in SU(2) does not change physical (observable) results of spin 1/2 in QM. I heard that he demonstrated his "analogy" for fun, but, probably, he reconned it as an "analogy" rather than as a "proof". There is nothing about it in his list of publications.

Comments

Did Dirac write about the trick in any of his books on quantum theory?

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As usual, Vladimir's statements are all wrong or misleading. Why does he waste his talents, his life and his time in this way?

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@Frank: Frank, frankly, point out where I am wrong or misleading, please. I wrote sincirely what I knew about the subject. For example, I have a full list of publications and the publications themselves in Russian (they were translated in Soviet times).