There are four types of pentagonal (five-sided) polyiamonds: D, M, P, and Q. Here I show the smallest known pentagonal polyiamond of each type that can be formed by copies of two pentiamonds, using at least one of each. If you find a smaller solution, please write.
See also
| 5IJ | D | M | P | Q |
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| 5IQ | D | M | P | Q |
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| 5IU | D | M | P | Q |
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| 5JQ | D | M | P | Q |
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| 5JU | D | M | P | Q |
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| 5QU | D | M | P | Q |
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Last revised 2026-08-07.