Primitive Perfect Isosceles Right Triangled Square

Title: _ 20:234BI GHM

Order: 20

Horizontal side: 234 Vertical side: 234

Elements: 8, 8√2, 14, 16, 12√2, 14√2, 16√2, 28, 42, 35√2, 56, 47√2, 70, 82, 66√2, 94, 70√2, 82√2, 140, 152.

Code: 1525 0 82 1401 140 234 662 206 168 941 234 234 423 206 126 285 206 140 145 206 126 144 220 126 706 164 70 166 148 110 567 164 126 86 140 102 165 148 94 85 140 94 124 152 82 476 117 47 827 0 82 820 82 82 354 117 47 705 164 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)