A polyiamond tri-oddity
is a figure with ternary symmetry formed by some number of copies of
a polyiamond that is not a multiple of three.
Torsten Sillke first studied them in 1996.
Here are the minimal known tri-oddities for polyiamonds of order
up to 6.
Impossible polyiamonds are shown in black.
Please write if you find a smaller solution or solve an unsolved case.
For heptiamonds (7-iamonds), see Heptiamond
For polyhexes, see Polyhex Tri-Oddities.
| Mirror Symmetry
These figures have mirror symmetry as well as ternary symmetry.
Last revised 2021-12-02.
Back to Polyform Oddities
Col. George Sicherman