Collision rays originate at center of cube and extend to each vertex. Collisions are indicated by "hit" text in the console. Note that collisions do not register if rays intersect the back side of a mesh (in particular, if the origin of the rays are contained in the target mesh).
Credit:
Modified from the example at http://stemkoski.github.io/Three.js/Collision-Detection.html by Lee Stemkoski.