Primitive Perfect Isosceles Right Triangled Square

Title: __ 19:96AS GHM

Order: 19

Horizontal side: 96 Vertical side: 96

Elements: 1√2, 2, 2√2, 6, 6√2, 12, 16, 18, 21, 23, 18√2, 21√2, 24√2, 34, 25√2, 46, 48, 50, 48√2.

Code: 505 0 46 484 48 48 483 96 48 24 50 46 186 34 30 212 73 27 211 73 48 237 73 48 246 72 24 465 0 0 341 34 46 167 34 46 185 34 12 23 73 25 250 71 25 14 72 24 121 46 12 62 52 6 61 52 12

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)