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. 2006 Jul 3;103(28):10612–10617. doi: 10.1073/pnas.0601389103

Table 3.

Typical Irish tetrahedra

Points Irish high: 8 symmetries
Irish medial: 3 symmetries
Irish low: 2 symmetries
Coordinates Type Coordinates Type Coordinates Type
Vertices (−1/4, 1/2, 0) + (0, 0, 0) 0 (0, 0, 0) +
(1/4, 1/2, 0) + (0, 1/4, 1/2) + (−1/4, 1/2, 0) +
(0, 1/4, 1/2) + (1/2, 0, 1/4) + (1/4, 1/2, 0) +
(0, 3/4, 1/2) + (1/4, 1/2, 0) + (0, 1/4, 1/2) +
Node (0, 1/2, 1/4) (5/24, 5/24, 5/24) 03 (−5/32, 0, 10/32) 0

Dodecahedral cells have nuclei 0, 1, 2, or 3 and volume 125/1024. Dodecadihedral ones have nuclei + and volume 129/1024. Here 03 = (7/12)·0 + (5/12)·3 and 0 = (5/8)· + (3/8)·0. Nodes are all points , 01, 12, 23, 30, 03, 10, 21, 32, 0, 1, 2, or 3 with above proportions.