Here I show the smallest known pentagonal (five-sided) polyiamonds that can be formed by copies of two hexiamonds, using at least one of each. If you find a smaller solution, please write.
In pentagonal polyiamonds, the numbers of cells pointing up and pointing down are never equal. So at least one of the hexiamonds used must have unequal numbers of cells pointing up and down. The only such hexiamonds are F and P.
See also
Last revised 2024-07-30.