# Heptiamond Tri-Oddities

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 heptiamonds (7-iamonds).
Unsolved heptiamonds are shown in grey.
Please write if you find a smaller solution or solve an unsolved case.

For polyiamonds with fewer than 7 cells, see
Polyiamond Tri-Oddities.
For polyhexes, see Polyhex Tri-Oddities.

## Arbitrary Solutions

## Holeless Variants

These solutions have horizontal mirror symmetry as well as ternary symmetry.

*Last revised 2017-09-02.*

Back to Polyform Oddities
<
Polyform Curiosities

Col. George Sicherman
[ HOME
| MAIL
]