Assertion: icosahedron's vertex | /r/AtLocation | top
Facets:
Source sentences:
text: If you hold an icosahedron so that one vertex is on top and one is on bottom, you'll see that its vertices are arranged in 4 horizontal layers.
text: In other words, only the tetrahedron has the property that you can rest it face-down on a table and not have a face on top; instead, a vertex is on top.