Given a clock, rearrange six consecutive numbers on its face, so
the sum of every pair of adjacent numbers is a prime.
There are two solutions. In each of these, the numbers from 5 to 10 are reordered.
1 2 3 4 7 10 9 8 5 6 11 12
1 2 3 4 9 10 7 6 5 8 11 12