Fair Use

With labels like "fair use" and "prior art",
Derivative defended its existence:
"Oh surely you can tell us two apart?
This nitpicking, this insolent insistence
that every sentence be a pure creation --
are alphabets exempt from this demand,
or do they too require a citation?
How would a reader try to comprehend --
without a common canon on their tongue --
the latticework of paragraphs and commas
that place a given writer's work among
those that transcend their periods; the dramas
that we still cherish -- and their use is free.
How are we then to be, or not to be?"