A time traveler who makes a living as an antiquities dealer tells a tale of a Greek urn that
appeared in two different places at the same time.
If the Time Traveller sold his wares directly from the maker, modern tests would show
that they are only a few years old. They are stored in an underground cavern somewhere in
the Pliocene to rack up the appropriate number of centuries, so that tests for
thermoluminescence and cosmic ray tracks give the right answer.