If you’re trying to write a story, be it for National Novel Writing Month or just for fun, you’ll have to face a blank page eventually. The seeds of an idea can help your story grow, blooming into a sweet rose of romance or a carnivorous tale of horror. Without those ideas, all that’s left is a blinking cursor… and frustration.
English bell ringing (called change ringing) has many connections to mathematics, notably to group theory and Hamiltonian cycles. My wife, Joan Hutchinson, is an ardent bell ringer (having rung in both England and North America), and I knew the basics of this ancient craft. A recent puzzle book by Mark Davies  inspired me to bring Mathematica’s integer-linear programming (ILP) capabilities to bear, but I wanted to go beyond puzzles and develop a new ringing method that would be of interest to the bell-ringing community.
In 2020, Melbourne, Australia, had a 112-day lockdown of the entire city to help stop the spread of COVID-19. The wearing of masks was mandatory and we were limited to one hour a day of outside activity. Otherwise, we were stuck in our homes. This gave me lots of time to look into interesting problems I’d been putting off for years.
I was inspired by a YouTube video by David Oranchak, which looked at the Zodiac Killer’s 340-character cipher (Z340), which is pictured below. This cipher is considered one of the holy grails of cryptography, as at the time the cipher had resisted attacks for 50 years, so any attempts to find a solution were truly a moonshot.