Primitive Perfect Isosceles Right Triangled Square

Title: __ 19:108AB GHM

Order: 19

Horizontal side: 108 Vertical side: 108

Elements: 4√2, 8, 8√2, 14, 11√2, 16, 22, 16√2, 28, 20√2, 34, 26√2, 28√2, 40, 48, 34√2, 37√2, 40√2, 60.

Code: 405 0 68 404 40 68 603 80 48 287 80 108 286 80 80 162 96 64 342 34 34 204 20 48 163 96 48 82 104 56 83 104 48 42 108 52 266 82 26 141 34 48 487 34 48 116 71 37 227 82 48 370 71 37 343 34 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)