puzzle

puzzle (http://definr.com/puzzle)

     n 1: a particularly baffling problem that is said to have a
          correct solution; "he loved to solve chessmate puzzles";
          "that's a real puzzler" [syn: puzzler, mystifier]
     2: a toy that tests your ingenuity
     v 1: be a mystery or bewildering to: "This beats me!" "Got me--I
          don't know the answer!" [syn: perplex, get, mystify,
           baffle, beat, bewilder, flummox, stupefy, stupify,
           nonplus, gravel, amaze, dumbfound]
     2: be uncertain about; think about without fully understanding
        or being able to decide; "We puzzled over her sudden
        departure"