Primitive Perfect Isosceles Right Triangled Square

Title: _d 19:204AJ GHM

Order: 19

Horizontal side: 204 Vertical side: 204

Elements: 1√2, 2, 2√2, 4, 5√2, 6√2, 7√2, 9√2, 16√2, 32, 32√2, 54, 64, 70, 86, 102, 118, 86√2, 102√2.

Code: 1185 0 86 1024 102 102 1023 204 102 164 118 86 76 127 95 62 140 96 701 204 102 56 135 91 645 140 32 90 127 95 10 135 91 27 134 90 26 134 88 45 136 86 867 0 86 860 86 86 541 140 86 324 172 0 323 204 0

The properties below may precede order:side in a tiling's title:

• c = crossed. There is a tile-corner traversed by two lines. The only known crossed PPIRTS's below order 20 are 19:35AB1of4 and 19:35AB4of4.
• d = double-pentagon patterned. Every such tiling is a subdivision of an instance of the same deformable tiling by two 45-90-90-90-225 pentagons with a shared side, four triangles and two pseudotriangles. All below order 19 are degenerate in the sense that one or more sides of underlying tiles have shrunk to zero length. The non-degenerate d-tilings of order 19 are 19:221AA, 19:229AB and 19:241AA.
• e = elegant. No tile-corner is just a T-junction. Such tilings may be considered aesthetically pleasing. The only known elegant PPIRTS's below order 16 are 13:21AA, 14:26AJ, 14:35AA and 15:55AA.
• i = isomers exist which are ineligible for this catalogue. They are not included in the isomer count which follows 'of' in the tiling id.
• r = rectangular inclusion. The only known PPIRTS's below order 16 with a rectangular inclusion are 13:18AA1-4of4 and 15:44AA1-4of4.

Credit for Discovery

Just three people are credited with the discovery of Primitive Perfects:

Geoffrey H. Morley (GHM, England)

Jasper D. Skinner, II (JDS, United States)

William T. Tutte (WTT, Canada, 1917-2002) (15:44AI, 17:136AJ and 19:56AJ only)

118
102√2
102
16√2
7√2
6√2
70
5√2
64
9√2
1√2
2
2√2
4
86
86√2
54
32√2
32