The tritetrahedron, also called the "boat polyhedron," is the name given in this work to the concave (non-regular) octahedron formed by joining three regular tetrahedra around a common edge and dropping inner faces. It is therefore precisely a 3-tetrahedral ring.
The tritetrahedron is implemented in the Wolfram Language as PolyhedronData[
"TetrahedralRing",
3
].
Rather surprisingly, the net shown above gives the triterahedron using the edge labeling of the left figure while the labeling shown in the right figure gives the usual regular octahedron.
The skeleton of the tritetrahedron is the tritetrahedral graph.
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Geocombinatorics 30, 5-13, 2020.de Grey, A. and Haugstrup,
A. "Two Small 6-Chromatic Unit-Distance Graphs in 
." Geocombinatorics 31, 110-115, 2022.