Assertion: octahedron's ax | /r/HasProperty | 1 per axis
Facets:
Source sentences:
text: ditto by an angle of 180°: 3 axes, 1 per axis, together 3 ((1 2) (3 4), etc.
text: ; i , j , k ) rotation about an axis from the center of an edge to the center of the opposite edge by an angle of 180°: 6 axes, 1 per axis, together 6 ((1 2), etc.