While recently in London, I attended a wonderful, candlelit concert– several Bach Brandenburg Concertos performed on original instruments– at St-Martin-in-the-Fields Church. These pieces (6 in all), which were presented to Christian Ludwig Margrave of Brandenburg-Schwedt in 1721, are regarded as the epitome of Baroque composition.
The Fourth ( in G M) was especially enjoyable, since I myself, in my day, performed it tens of times throughout Israel.

Yet the next day, meeting one of the church bell ringers was just as memorable. The 19 year old, who has been ringing bells since he was 6, carries a small book full of intriguing belling-sequence notations, all of which, he allows, he has nearly learned by heart. And the accent is on heart– his eyes glowed as he described his hobby, his heritage (his father and his father before him were bell ringers as well) and the joy of pealing out joy.
So if you hear bells at St-Martins on Sundays…..

According to Wiki,
Method ringing in action
The plain course
This defines the changes over a relatively short sequence, ranging from a mere handful up to a few hundred changes at most. To learn this, a ringer must memorize the course taken by his or her bell during this span, called the plain course. To help learn it, ringers often use a diagram in which a plain course is written out, row by row, and a particular bell’s course is given visual shape, being traced by a blue line.
A method’s plain course begins and ends in rounds and thus can be considered as a performance in its own right, albeit a brief one.
Calls and compositions
In a longer peal, the plain course is repeated a number of times, but with defined break points at which one of the ringers, who is also acting as conductor, makes a call directing the ringers to make a slight variation in the course. (The most common calls are called bobs and singles.)
Ta-da!