Alternated hexagonal tiling honeycomb
In three-dimensional hyperbolic geometry, the alternated hexagonal tiling honeycomb, h{6,3,3}, or , is a semiregular tessellation with tetrahedron and triangular tiling cells arranged in an octahedron vertex figure. It is named after its construction, as an alternation of a hexagonal tiling honeycomb.
Source: Wikipedia — Alternated hexagonal tiling honeycomb (CC BY-SA 4.0)