Plagiarism detection tricks

Heraclides amazingly proposed (back then) that earth has a 24 hour cycle of revolution on its axis.  However  he wasn’t as perceptive in other matters:

“Dionysios had written a tragedy which he called Parthenopaeus.  As a practical joke, he put Sophocles as the author when it was written .   When Heraclides quoted as if it really was by Sophocles in one of his works.  Then Dionysius told him it was a joke but of course Heraclides didn’t believe him at all.  Then Dionysius told to look at at thethe opening eight lines.  The first letter spelled the name of his lover, Pancalus.  Then Heraclides said that this may have been coincidence.

Then Dionysius told him that he could also find an acrostic which said “Old monkeys do not fall into traps.  Well, they do in fact but it takes a long time.”  He had also hidden in the manuscript as an acrostic the phrase “Heraclides is not ashamed that he doesn’t understand writing.”

Lives of the Philosophers – Diogenes Laertius