an octagon
octagonal pyramid :)
The answer to your question, is an Octahedron.
An octagonal pyramid
An octagonal pyramid.
A regular octagonal pyramid.
trianglular pyramid trianglular pyramid
octagonal pyramid
This object is called an octahedron
This is an Octahedron!
That would be a regular octahedron. See http://en.wikipedia.org/wiki/Octahedron
A regular octahedron.