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Mind-boggling puzzles

Posted By: Timothy Chow
Date: Thursday, 10 June 2010, at 5:25 a.m.

In Response To: Now with six-point prime, please :) (Matt Cohn-Geier)

MCG wrote:

Do you ever feel like you are really different from other people somehow?

Since this question seems to have been prompted by Nack's unusual puzzle, let me just say that while I like Nack's puzzles, if you find them so bizarre that you are led to wonder what kind of twisted mind could invent them, then you ain't seen nothin' yet. I've seen thousands of weird and wonderful puzzles of all kinds, but the ones that boggle my mind the most are record-breaking retrograde chess problems. For a random example, see this chess position, which can be reached after Black's 183rd move, and where it is believed that there is a unique way to reach it after Black's 183rd move. "Unique" is meant in a strong sense here; in particular, even a "trivial" transposition of moves that reaches the same position means that the solution is not unique. Note the date of composition (1947) which was before modern computers.

Messages In This Thread

• Fifteen checkers on the bar, fewest moves
  Nack Ballard -- Wednesday, 9 June 2010, at 2:35 a.m.
  • Fifteen checkers on the bar, fewest moves
    Daniel Murphy -- Wednesday, 9 June 2010, at 3:51 a.m.
    • Fifteen checkers on the bar, fewest moves
      Stick -- Wednesday, 9 June 2010, at 3:59 a.m.
      • Fifteen checkers on the bar, fewest moves
        Daniel Murphy -- Wednesday, 9 June 2010, at 4:22 a.m.
        • Fifteen checkers on the bar, fewest moves
          Christian Munk-Christensen -- Wednesday, 9 June 2010, at 7:54 a.m.
  • Fifteen checkers on the bar, fewest moves
    Michael Nielsen -- Wednesday, 9 June 2010, at 5:06 p.m.
    • 7 rolls
      Michael Nielsen -- Wednesday, 9 June 2010, at 6:19 p.m.
      • 7 moves of course *NM*
        Michael Nielsen -- Wednesday, 9 June 2010, at 6:27 p.m.
      • 7 rolls
        Ray Kershaw -- Wednesday, 9 June 2010, at 7:37 p.m.
      • Now with six-point prime, please :)
        Nack Ballard -- Thursday, 10 June 2010, at 12:32 a.m.
        • Now with six-point prime, please :)
          Matt Cohn-Geier -- Thursday, 10 June 2010, at 12:34 a.m.
          • Now with six-point prime, please :)
            Nack Ballard -- Thursday, 10 June 2010, at 1:00 a.m.
            • Now with six-point prime, please :)
              Daniel Murphy -- Thursday, 10 June 2010, at 1:25 a.m.
              • Slot Rule (a.k.a. "slotgammon")
                Nack Ballard -- Thursday, 10 June 2010, at 1:45 a.m.
            • Now with six-point prime, please :)
              Matt Cohn-Geier -- Thursday, 10 June 2010, at 1:25 p.m.
              • Now with six-point prime, please :)
                Timothy Chow -- Thursday, 10 June 2010, at 3:30 p.m.
                • Now with six-point prime, please :)
                  Matt Cohn-Geier -- Thursday, 10 June 2010, at 6:22 p.m.
          • Mind-boggling puzzles
            Timothy Chow -- Thursday, 10 June 2010, at 5:25 a.m.
            • OT: Another example
              Timothy Chow -- Thursday, 10 June 2010, at 5:31 a.m.
              • OT: Another example
                Nack Ballard -- Thursday, 10 June 2010, at 7:15 a.m.
                • OT: Another example
                  Timothy Chow -- Saturday, 12 June 2010, at 1:05 a.m.
                  • OT: Another example
                    Nack Ballard -- Saturday, 12 June 2010, at 4:04 a.m.
  • Fifteen checkers on the bar, fewest moves
    Keene -- Wednesday, 9 June 2010, at 6:35 p.m.
    • Fifteen checkers on the bar, fewest moves
      Nack Ballard -- Thursday, 10 June 2010, at 12:18 a.m.