Remember the Bellini and Cellini families? The ones who back in the day made caskets? The families were best of friends and would often collaborate on making a set of caskets. Bellini and his sons only put true inscriptions on the ones they made, and Cellini and his sons only put false inscriptions on the ones they made.
I recently encountered a set of caskets inscribed as follows:
Casket A: At least one of these caskets was made by one of the sons.
Casket B: At most one of these caskets was made by a member of the Bellini family.
Who made each casket?
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Consider the statement on casket B. If it is false, then both caskets were made by members of the Bellini family. But then you'd have a Bellini-inscribed casket with a false statement, which is a contradiction. So the statement on casket B must be true, which means it was made by a member of the Bellini family. Thus, B must be the "at most one" casket made by a member of the Bellini family, so A was made by a member of the Cellini family.
Therefore, the statement on casket A is false. Neither casket was made by one of the sons, so since the statement on A is false and the one on B is true, A was made by Cellini himself and B was made by Bellini himself.