I was thinking about maple keys recently.

The maple key is an interesting schema of a taxonomy; the kernel is like a category node – the top-level domain. Each vein in the wing of the seed branching away from the node is a trace of the path along which the line of membership in the category emerges as an [instance] of a membership [type].

On a slightly more abstract note, the veins also forecast a resemblance of the future roots and branches of the eventual tree, and in a way alluding to the further growth of category membership as each tree root eventually supports the life of the tree so that each tree branch can ultimately produce more seeds so that it might perpetuate, exponentially, the life of this tree of knowledge.