Assertion: icosahedron's face | /r/CapableOf | remain unchanged
Facets:
Source sentences:
text: It was thought for a long time that all polyhedrons are rigid, in the sense that if all faces and edges remain unchanged, and only the angle between the faces could change (the edges act as hinges) then no movement could be made.
text: Another four faces, of the original 20, remain unchanged.