Primitive Perfect Isosceles Right Triangled Square

Title: __ 19:162AC GHM

Order: 19

Horizontal side: 162 Vertical side: 162

Elements: 5√2, 10, 10√2, 20, 20√2, 23√2, 35, 26√2, 29√2, 46, 35√2, 52, 58, 46√2, 49√2, 52√2, 75, 58√2, 64√2.

Code: 585 0 104 584 58 104 236 93 139 467 116 162 466 116 116 640 93 139 522 52 52 294 29 75 494 78 26 753 127 0 202 147 55 201 147 75 102 157 65 101 157 75 52 162 70 356 127 35 523 52 0 262 78 26 355 127 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)