Primitive Perfect Isosceles Right Triangled Square

Title: _r 19:124AA2of4 GHM

Order: 19

Horizontal side: 124 Vertical side: 124

Elements: 6, 6√2, 18, 13√2, 16√2, 26, 30, 32, 24√2, 26√2, 30√2, 32√2, 46, 48, 36√2, 52, 39√2, 42√2, 46√2.

Code: 465 0 78 464 46 78 166 76 108 327 92 124 326 92 92 246 52 84 485 76 60 63 52 78 422 94 42 527 0 78 396 13 39 181 94 60 307 94 60 306 94 30 66 88 36 130 13 39 360 88 36 267 0 26 260 26 26

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)