Ringing the changes

The ancient and continuing art of change ringing, or campanology (how the British ring church bells), is studied from a mathematical viewpoint. An extent on n bells is regarded as a hamiltonian cycle in a Cayley colour graph for the symmetric group Sn, embedded on an appropriate surface. Two methods for variable n (Plain Bob for all n and Grandsire for n =; 3 (mod 4)) are discussed, and a new method for n odd is introduced. All minimus methods (n = 4) and five doubles methods (n = 5) are depicted, one of these being the new No Call Doubles.