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The Mirror of Erised

Snape's Logic Puzzle

The ghost of Severus Snape glares at you and speaks:

“I may be dead, but it's still my job to guard this chamber and the sorcerer's stone. This logic puzzle consists of several statements that I make, each one either true or false. There are exactly twenty­-nine statements.

  1. This puzzle contains exactly four misspelled words.
  2. Statements 3 and 4 have the same truth value.
  3. Statement 17 is true.
  4. Statements 1 and 21 have the same truth value.
  5. The number of letters in the answer is equal to the total number of false statements among this one and the following six.
  6. Statements 16 and 26 are both false.
  7. Not all three of statements 7, 20, and 26 have the same truth value.
  8. The second statement in this puzzle is false.
  9. The answer is a Caesar shift of a common animal.
  10. If statement 19 is true, then this statement's truth value is the same as that of statement 15.
  11. The answer to this puzzle is the name of a major American city with two letters added.
  12. Among statements 12, 18, and 29, no more than one is true.
  13. The first statement in this puzzle is true.
  14. Among statements 8, 11, 13, and 14, at least two are false.
  15. The answer to this puzzle is "SEVERUS SNAPE IS MUCH CLEVERER THAN I AM".
  16. The final statement in this puzzle is false.
  17. This statement has the same truth value as statement 29.
  18. The total value of the answer as a Scrabble word is equal to the number of words in the last false statement in this puzzle.
  19. Statements 6 and 17 are both true.
  20. The second and third letters of the answer are not both vowels.
  21. The third and fourth statements in this puzzle have opposite truth values.
  22. Among statements 3, 5, and 22, an odd number are false.
  23. The number of true statements among 6, 23, and 24 is not exactly one.
  24. The first and last letters of the answer are alphabetically consecutive.
  25. The answer, when written in Morse code, has equal numbers of dots and dashes.
  26. If statement 8 is true, then statement 13 is true.
  27. Either statement 9 implies statement 17, or this statement is false.
  28. Among statements 4, 25, and 28, an even number are true.
  29. Statement 2 is false.

I'm sure you and your friends will have no trouble whatsoever solving this. It is a straightforward logic puzzle with no nasty tricks.”