# Tetrahedral Trinja Star

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Pictures copyright by
PhotoArt Studio HĂ¶rby
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This model was built in October 2019 and its dimensions is around 7 cm x 7 cm x
7cm.
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This polyhedron only consists of regular heptagons that are folded over a
diagonal. There are different ways in which you can fold a regular heptagon and
for this polyhedron the folding is done in a 'W' shape.
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The polyhedron has the same rotational symmetry as a tetrahedron, i.e. without
the reflections. I like these kind of symmetries where the reflections are
missing. I found Nemesis first, then I understood
that the heptagons were organised in triplets around a star with three
points. I thought that this variant might exist with tetrahedral and octahedron
symmetry as well. Then I led a search program towards this one.
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Polyhedra that lack reflections are usually a bit more challenging to build and
Nemesis was no exception. Since I found the right build strategy for that one
before, it was not a problem building this one using the same strategy.
The search program found two variants of this one. In the interactive 3D model
you can choose which one to look at.
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Here is the same model while more or less looking into an order two symmetry axis.
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## Last Updated

2019-12-09