Pentiamond-Heptiamond Pair Pentagons

Introduction

A pentiamond is a plane figure formed by joining 5 equal equilateral triangles edge to edge. There are 4 pentiamonds:

A heptiamond is a plane figure formed by joining 7 equal equilateral triangles edge to edge. There are 24 heptiamonds:

Here I show the smallest known pentagonal (five-sided) polyiamonds that can be formed by copies of a pentiamond and a heptiamond, using at least one of each. If you find a smaller solution, please write.

See also

  • Pentiamond-Hexiamond Pair Pentagons
  • Hexiamond Pair Pentagons
  • Heptiamond Pair Pentagons
  • Table

    This table shows the number of cells in the smallest known solution for a given pentiamond and heptiamond. Colors indicate types of pentagons.

     7A7B7C7D7E7F7G7H7I7J7K7L7M7N7P7Q7R7S7T7U7V7X7Y7Z
    5I371717173441171917492212122947173731229990493739
    5J3436393432172417296239173236397129346247391045169
    5Q361093617?1717871217?31121717?17??8436?7917
    5U????189?6010519??1760???????????

    12 Cells

    17 Cells

    19 Cells

    22 Cells

    24 Cells

    29 Cells

    31 Cells

    32 Cells

    34 Cells

    36 Cells

    37 Cells

    39 Cells

    41 Cells

    47 Cells

    49 Cells

    51 Cells

    60 Cells

    62 Cells

    69 Cells

    71 Cells

    79 Cells

    84 Cells

    87 Cells

    90 Cells

    99 Cells

    104 Cells

    105 Cells

    109 Cells

    189 Cells

    Last revised 2025-03-08.


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    Col. George Sicherman [ HOME | MAIL ]