Primitive Perfect Isosceles Right Triangled Square

Title: __ 19:150AB GHM

Order: 19

Horizontal side: 150 Vertical side: 150

Elements: 5√2, 10, 10√2, 12√2, 20, 24, 18√2, 27, 30, 24√2, 36, 40, 48, 40√2, 57, 48√2, 55√2, 80, 75√2.

Code: 752 75 75 554 55 95 400 110 150 401 150 150 50 70 110 801 150 110 100 65 105 101 75 105 575 75 48 201 75 95 273 75 48 480 48 48 481 96 48 242 120 24 361 132 48 182 150 30 303 150 0 243 120 0 122 132 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)