tetrahedral

To get a sense of why this fact about geodesics is true on four of the five Platonic solids, we’ll take a “tumbling” approach to these paths, and we’ll switch over to a tetrahedral world where tumbling paths are a little easier to study.
The Crooked Geometry of Round Trips|Patrick Honner|January 13, 2021|Quanta Magazine
To the south, 27 E., is a tetrahedral peak, which our guide called Ngoma-dingding.
Trans-Himalaya, Vol. 2 (of 2)|Sven Hedin
The spores of this species are spheroid-tetrahedral, the three radiating angles marked with slender vittæ, or bands.
Beautiful Ferns|Daniel Cady Eaton
It crystallizes in the cubic system; with regular octahedral and tetrahedral cleavages; spec.
A Dictionary of Arts, Manufactures and Mines|Andrew Ure

The tetrahedral or Reye complex is the simplest and best known of proper quadratic complexes.
Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6|Various
Polar spines very thick and short, tetrahedral, one-fourth as long and broad as the major axis.
Report on the Radiolaria Collected by H.M.S. Challenger During the Years 1873-1876, First Part: Porulosa (Spumellaria and Acantharia)|Ernst Haeckel

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