Octagon Dissections

Author : Gavin Theobald

{3} Triangle
{4} Square
{5} Pentagon
{6} Hexagon
{7} Heptagon
{9} Enneagon
{10} Decagon
{11} Hendecagon
{12} Dodecagon
{16} Hexadecagon
{5/2} Pentagram
{6/2} Hexagram
{8/2} Octagram
{8/3} Octagram
{10/2} Decagram
{12/2} Dodecagram
{12/3} Dodecagram
{16/2}  Hexadecagram
{R√2} Silver Rectangle
{Rϕ} Golden Rectangle
{R2} Domino
{R×} Optimised Rectangle
{G} Greek Cross
{L} Latin Cross
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
7 5 9 8 8 7 1110 1 12 10 1615 10 17


5/2 6/2 7/2 7/3 8/2 8/3 9/2 9/3 9/4 10/2 10/3 10/4 12/2 12/3 12/4 12/5
10 8 11 6 1312 12 12


Triangle — Octagon (7 pieces)

Both of these are TT2 dissections.


Square — Octagon (5 pieces)

This dissection first appeared in the circa 1300AD anonymous Persian manuscript “Interlocks of Similar or Complementary Figures”.


Pentagon — Octagon (9 pieces)

Pentagon — Octagon (8 pieces with 1 turned over)


Hexagon — Octagon (8 pieces)

Hexagon — Octagon (7 pieces with 2 turned over)


Heptagon — Octagon (11 pieces)

Heptagon — Octagon (10 pieces with 1 turned over)


Octagon — Enneagon (12 pieces)


Octagon — Decagon (10 pieces)

The two overlays show the strips before and after the modification of the decagon strip that saves a piece.

Octagon — Hendecagon (16 pieces)
Octagon — Hendecagon (15 pieces with 1 turned over)


Octagon — Dodecagon (10 pieces)


Octagon — Hexadecagon (17 pieces)


Octagon — Pentagram (10 pieces)


Octagon — Hexagram (8 pieces)


Octagon — Octagram {8/2} (11 pieces)


Octagon — Octagram {8/3} (6 pieces)

Discovered by Harry Lindgren.


Octagon — Decagram {10/2} (13 pieces)
Octagon — Decagram {10/2} (12 pieces with 1 turned over)


Octagon — Dodecagram {12/2} (12 pieces)


Octagon — Dodecagram {12/3} (12 pieces)


Octagon — Hexadecagram {16/2} (16 pieces with 4 turned over)

Discovered by Greg Frederickson (1997).


Octagon — Silver Rectangle (4 pieces)


Octagon — Golden Rectangle (6 pieces)


Octagon — Domino (6 pieces)


Octagon — Optimised Rectangle (4 pieces)


Octagon — Greek Cross (8 pieces)


Octagon — Latin Cross (8 pieces)