Rounded Polyiamonds are formed by joining unit equilateral triangles edge-to-edge or corner-to-corner. The cornerwise joints are regarded as solid, unlike those of polymings, which may cross at these points. and the pieces are fixed in the regular triangular grid.
Rounded Moniamond - 1 (1 tile)
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Rounded Diamonds - 3 (6 tiles)
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| 1 | 2 | 3 |
Rounded Triamonds - 11 (33 tiles) The letters are George Sicherman's notation for the equivalent polyming pieces.
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| 1 | 2 | 3 | 4 | 5 | 6 |
| I | P | E | L | S | A |
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| 7 | 8 | 9 | 10 | 11 | |
| Y | R | T | U | J |
For higher orders of rounded polyiamond, the number of pieces is as follows:
Rounded Tetriamonds - 82
Puzzles using Rounded Polyiamonds