mrdoob/three.js — pull request #638 by clockworkgeek (2011-10-10 17:58:12+00:00)
Title: Octahedron subdivisions to default to 0.

Just realised that if created with no extra parameters a programmer would expect an Octahedron class to make an octahedron. It is common sense that an unspecified level of detail should be equivalent to zero, please include this minor update.