March 2007

## Clock Sudoku

Here is the second installment of our series of Sudoku variations. It was kindly provided by Brainfreeze puzzles, a puzzle making company run by the mathematician Laura Taalman and the software developer Philip Riley, whose book Color Sudoku will be available in the spring.

Fill the rings with the numbers from 1 to 12 so that no number is repeated in any of the six rings, any of the six shaded double-wedges, or any of the pairs of opposite wedges. Have fun!

If you are stumped by last issue's puzzle, here is the solution.

For some challenging mathematical puzzles, see the NRICH puzzles from this month or last month.