Coding classes in Leicestershire

Number six bells 1 to 6, highest to lowest. Ringing them in order, 123456, is called rounds. Every row that follows is a new order, and the rule is strict: between one row and the next, each bell may move at most one place. That means a new row is made by swapping some neighbouring pairs and leaving other bells where they are. The goal, an extent, is to ring all 720 orders of six bells exactly once and come back to rounds. The first things a learner codes are the swap and the checker: a function that reads a list of rows and says whether any repeats and whether any bell ever jumped two places.

The third row is the heart of the project. A lead is twelve rows; the first one, from rounds, ends on 132546, and the plain lead end turns that into 135264 to start the next. A bob changes that lead-end step, and a composition is a list of choices, plain or bob, one per lead. Our program tries them depth first: add a lead, check that none of its twelve rows has been rung before, carry on, and back up when it gets stuck. With only plain leads and bobs it explored 30,074 positions in 0.6 seconds and ran out of options without ever reaching 720. Because the search tried everything, that is not a failure to find an answer. It is a proof that there is none.

Allow a third call, the single, which swaps just the last two bells at a lead end, and the same search finds a true 720 at its 434th position: 60 leads, of which 43 are plain, 7 are bobs and 10 are singles. Then the checker, written separately, confirms it: 720 rows, no repeats, no bell ever moving more than one place, ending in rounds. A good learner never trusts a search result that has not been checked by different code.

So the reason to learn to code in Leicestershire in 2026 is not speed at typing programs. It is knowing when a program's silence is an answer. The longer argument is in why teenagers should still learn to code in 2026.