Primitive Perfect Isosceles Right Triangled Square

Title: __ 19:302AB GHM

Order: 19

Horizontal side: 302 Vertical side: 302

Elements: 3√2, 12√2, 24, 24√2, 48, 58, 64, 48√2, 58√2, 87, 93, 96, 116, 122, 87√2, 128, 93√2, 116√2, 122√2.

Code: 1287 0 302 1160 128 302 1161 244 302 582 302 244 581 302 302 1226 180 122 126 0 174 247 12 186 246 12 162 487 36 186 486 36 138 967 84 186 936 87 93 647 180 186 872 87 87 1225 180 0 36 84 90 935 87 0 873 87 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)