Primitive Perfect Isosceles Right Triangled Square
Title: _ 20:294AI GHM
Order: 20
Horizontal side: 294 Vertical side: 294
Elements: 2, 2√2, 4, 6, 5√2, 6√2, 7√2, 10, 34, 34√2, 68, 90, 68√2, 102, 124, 90√2, 136, 102√2, 170, 192.
Code: 1927 0 294 1243 192 170 1027 192 294 1026 192 192 72 199 185 50 199 185 26 192 178 45 194 176 101 204 180 902 294 90 25 192 176 67 192 176 60 198 176 686 0 102 1367 68 170 1703 204 0 685 0 34 903 294 0 345 0 0 344 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)