Edge-joined equilateral triangles of the triangular lattice, alternating point-up and point-down.
The 12 free hexiamonds.
| Figure | Order | Free | One-sided | Fixed | Verified |
|---|---|---|---|---|---|
| moniamond | 1 | 1 | 1 | 2 | ✓ 15/15 |
| diamond | 2 | 1 | 1 | 3 | ✓ 15/15 |
| triamond | 3 | 1 | 1 | 6 | ✓ 15/15 |
| tetriamond | 4 | 3 | 4 | 14 | ✓ 15/15 |
| pentiamond | 5 | 4 | 6 | 36 | ✓ 15/15 |
| hexiamond | 6 | 12 | 19 | 94 | ✓ 15/15 |
| heptiamond | 7 | 24 | 43 | 250 | ✓ 15/15 |
| octiamond | 8 | 66 | 120 | 675 | ✓ 15/15 |
| enneiamond | 9 | 160 | 307 | 1,838 | ✓ 15/15 |
| deciamond | 10 | 448 | 866 | 5,053 | ✓ 15/15 |
Reference sequences: Free A000577, One-Sided A006534, Fixed A001420.