Figure above :  Same crystal as in previous Figure.
Branches, as far as they can be discerned, are indicated (green). All branches correspond to directions of fastest growth (that is, faster than the prism faces parallel to the c-axis of the crystal [which is the crystal's main crystallographic axis, and at the same time the crystal's 6-fold rotation axis] )  The faces corresponding to these fast-growing directions are also vertical prism faces, but they have grown themselves out of existence, leaving six other possible vertical prism faces, that grew (intrinsically) at a lower rate.