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  • Billiard is Turing complete

    From ram@ram@zedat.fu-berlin.de (Stefan Ram) to comp.theory on Sat Sep 26 12:36:11 2026
    From Newsgroup: comp.theory

    A Billiard table with a single Billiard ball on it
    can perform any computation.

    "Two-dimensional billiards are Turing complete" (2026)
    - Eva Miranda et al.


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  • From Ross Finlayson@ross.a.finlayson@gmail.com to comp.theory on Sat Sep 26 05:49:53 2026
    From Newsgroup: comp.theory

    On 09/26/2026 05:36 AM, Stefan Ram wrote:
    A Billiard table with a single Billiard ball on it
    can perform any computation.

    "Two-dimensional billiards are Turing complete" (2026)
    - Eva Miranda et al.



    Given "the tools of geometry", ..., then besides
    also "the mechanics of billiards".

    "Compass and edge" might be "Turing complete",
    though it would involve all the pencil & paper
    in the world, and then some.


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