Well, the description is fairly accurate - it definitely is rare!
Reminds me of Monty Python:
"Half a bee, philosophically
Must, ipso facto, half not be
But half the bee has got to be
A vis-a-vis its entity, d'you see?
But can a bee be said to be
Or not to be an entire bee
When half the bee is not a bee
Due to some ancient injury?"