This week’s puzzle comes from my Science Times colleague Ben Carey, who tells me that you really don’t have to be smarter than a fifth-grader to solve it. I don’t take much consolation from his assurance, given that the puzzle utterly stumped me, but I respect Ben’s authority on the subject of fifth-graders and puzzles. He’s the author of “The Unknowns,” a novel for young adults, in which the pre-teen inhabitants of a trailer park have to solve a series of math puzzles in order to navigate a tunnel network and save their community from catastrophe.
My son, who’s in fourth grade, loved the novel and managed to pick the correct answer to this puzzle, but he confessed that he was guided by intuition and wasn’t able to give a logical explanation for his choice. (Maybe he’d have gotten it in fifth grade.) To be eligible for the solvers’ prize — a copy of “The “Unknowns” — you have to give a reason for the answer you choose below:
Amulet Books Consider the four shapes in the top row followed by a blank space in the fifth position. Which of the possibilities in the bottom row — the shapes labeled A, B, C, and D — would most logically belong in that fifth position?As usual, you can post your answer as a comment here, and submit another puzzle either as a comment or by emailing tierneylab@nytimes.com. (Please email me a solution to the puzzle and indicate whether or not it’s original.) I’ll award the prize to someone who comes up with an especially interesting answer or to someone who proposes a sufficiently intriguing puzzle for Lab readers to solve. The Lab judges may look kindly on answers given in verse, perhaps ones that delve into the theme of things unknown. Although we expect it will be difficult for anyone to supersede the philosophical musings on this subject by Donald Rumsfeld when he was secretary of defense:
. . . there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns — the ones we don’t know we don’t know.”
There is actually some logic to what he said — and to those shapes in this week’s puzzle. Hope you have better luck than I did.
And if you haven’t yet tried last Monday’s Russell Crowe Hotel Puzzle, today’s the last chance to try for the prize. Tomorrow we’ll announce the prize and discuss ways to find Mr. Crowe a room at the Hotel Infinity.
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