Re: Orange stacks

Liste des GroupesRevenir à r puzzles 
Sujet : Re: Orange stacks
De : richard (at) *nospam* cogsci.ed.ac.uk (Richard Tobin)
Groupes : rec.puzzles
Date : 14. Jul 2025, 15:00:51
Autres entêtes
Organisation : Language Technology Group, University of Edinburgh
Message-ID : <10532ij$1dhk1$1@artemis.inf.ed.ac.uk>
References : 1 2 3 4
User-Agent : trn 4.0-test76 (Apr 2, 2001)
In article <1052vlk$3dn0r$1@dont-email.me>,
David Entwistle  <qnivq.ragjvfgyr@ogvagrearg.pbz> wrote:

Then one shape (from the square pyramid) has a square top and bottom. It
looks to me like a truncated octahedron.

Top layer:

  .       .       .
 
      a       b

  .       .        .

      c       d

  .       .        .


Middle layer:

  e       f       g

      .        .

  h       i       j

      .        .

  k       l       m


Bottom layer:

  .       .       .

      n       o

  .       .        .

      p       q

  .       .        .

If you consider the octahedron based on the square f, h, j, and l,
then the balls on the top and bottom layers do not fall on its faces -
in fact they are directly above and below the edges of the square: a
is directly above the midpoint of hf and n below it, forming a square
face.

There are in fact 6 square faces: abcd, nopq, ahnf, bfoj, djql, and
clph.  And 8 triangular faces: abf, bdj, dcl, cah, nof, oqj, qpl, and
pnh.  This is a cuboctahedron.

The second shape (from the triangular pyramid) is based exclusively on
equilateral triangles and is entirely regular [...]

I can see I'm going to have to buy some golf balls, or table tennis balls.

You will find that the second shape is also not what you think it is.

-- Richard

Date Sujet#  Auteur
12 Jul 25 * Orange stacks12David Entwistle
12 Jul 25 +* Re: Orange stacks8Carl G.
14 Jul 25 i`* Re: Orange stacks7David Entwistle
14 Jul 25 i `* Re: Orange stacks6Richard Tobin
14 Jul 25 i  +* Re: Orange stacks2David Entwistle
14 Jul 25 i  i`- Re: Orange stacks1Richard Tobin
15 Jul 25 i  `* Re: Orange stacks3David Entwistle
15 Jul 25 i   `* Re: Orange stacks2Richard Tobin
21 Jul08:46 i    `- Re: Orange stacks1David Entwistle
12 Jul 25 +* Re: Orange stacks2Richard Tobin
14 Jul 25 i`- Re: Orange stacks1David Entwistle
16 Jul09:05 `- Re: Orange stacks1David Entwistle

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