Alice through the Looking-glass
Alice meets Tweedledee and Tweedledum in the forest. The brothers look so much alike that Alice cannot tell them apart. In our version of the story one of the brothers tells lies on Mondays, Tuesdays and Wednesdays but tells the truth on the other days of the week. The other brother lies on Thursdays, Fridays and Saturdays but is truthful on the remaining days of the week. One day Alice meets the two in the forest, and the following conversation takes place:
FIRST BROTHER: I am Tweedledum.
SECOND BROTHER: I am Tweedledee.
ALICE: Ah, so it’s Sunday.