Writing is also a distinctly human activity. It has been said that a monkey, randomly typing away on a typewriter (in the days when typewriters replaced the pen or plume as the preferred instrument of writing) could re-create Shakespeare-- but only if it lived long enough (this is known as the infinite monkey theorem). Such writing has been speculatively designated as coincidental. It is also speculated that extra-terrestrial beings exist who may possess writing. The fact is, however, that the only known writing is human writing.