One sentence. A person, or a machine.
—
The human sentences are real, and every one is from a book old enough to be out of copyright — which is the honest limitation of this game, because a machine can be asked to write like 1870 but a person from 1870 cannot be asked to write like anything else. So the model is told to write in the same register, and told not to reproduce or paraphrase any real sentence. A few of the human lines are famous enough that you may simply recognise them. That counts as a clue, not as cheating.