Assertion: octahedron's face | /r/CapableOf | lie on same plane
Facets:
Source sentences:
text: The triangular faces of each pair of adjacent pyramids lie on the same plane, and so merge into rhombuses.
text: A different form of the tetrakis hexahedron, formed by using taller pyramids on each face of the cube, is non-convex but has equilateral triangle faces that again lie on the same planes as the faces of the three octahedra; it is another of the known isohedral deltahedra.