Yes, I enjoyed the diagrams, thanks.
I like this
1998 definition of a Double Method, with my
emphases:
What is a double method? It has a special sort of symmetry. All regular methods are symmetrical - if you look at the 'blue line' you will find an axis of symmetry from which point the progress of the line is a mirror image of what has gone before. ...A double method has two axes of symmetry, so that the work on the front when the treble is at the back is the mirror image of the work at the back when the treble is at the front. In fact the whole of the work over the treble is a mirror image of the work under the treble. … Many double methods have double in their name - Double Bob, Double Oxford, Double Norwich - but some, most notably Bristol and Superlative Surprise, do not….
from the CCCBR publication
The Tower Handbook 1998 ISBN 0 900271 44 2 Complied by
.
The Council, in a new Decision at its
2004 meeting codified a Double Method for the first time, having relied on customary ringers’ terminology before this:
(E).A.7 - A method has palindromic symmetry if it is the same method when rung backwards, that is when the order of the changes is inverted. A method has double symmetry if it is the same method when reversed, that is when the places within each change are inverted. A method has rotational symmetry if it is the same method when reversed and rung backwards.
.
This definition survived in the Decisions until superseded by the Framework in
2018-2019, which phrased the rules as:
4.B.1. Palindromic Symmetry: A Method has Palindromic Symmetry if the same Changes result (after Rotation if needed) when read backwards, that is, when the order of the Changes is inverted.
4.B.2. Double Symmetry: A Method has Double Symmetry if the same Changes result (after Rotation if needed) when reversed, that is, when the Places within each Change are inverted.
4.B.3. Rotational Symmetry: A Method has Rotational Symmetry if the same Changes result (after Rotation if needed) when reversed and read backwards.
Double Methods, as defined in 1998, have a mathematical elegance, are artistically pleasing, help practical ringing and are an essential part of Ringing Heritage. (As an aside, the natural meaning of
Double is its
two-ness, and this is preserved. Also see here:
RevealOther ringers’ terminology respects the natural meaning of
Double. I can ring handbells double-handed and double dodges in Doubles with all double-changes and not be ringing a Double method. (
Stedman Doubles)
}
To redefine them, and to do that - in my assessment - accidentally, is a real shame and should be undone.
Turning to 2004, there had been no earlier Decision which tried to codify a Double Method. All ringers reading that new version would, as I did at the time, think it was good-enough. It would have been better to have a proper definition of “
rung backwards” to remove any ambiguity. (Brief aside here:
RevealThe term “
rung backwards” doesn’t have complete precision: surely starting
Plain Bob Minor backwards, with the change
12 will then have all the leading at backstroke-then-handstroke and not feel like Plain Bob Minor at all. Similarly
“Go Backward Hunt” is designed exactly to achieve wrong-leading.
) The Decisions were never designed-as-a-whole and there were all manner of quirks and ambiguities in the wording and it was just-in-passing to notice this one, and forgive it ...
The new Decision then goes on to say that if you now
reverse the method, and it is still the same method, then it is a Double Method. That too was wholly in line with the customary definition, while talking of the overwhelmingly predominant (then as now, see current example here:
RevealFor an example of this overwhelming predominance, consider the 2023 Ringers’ Diary, Start from the 1stJanuary and work backwards through the method pages, counting the bluelines and how many are symmetric. For the impatient, click here:
Reveal
- Maximus: 18 bluelines, all symmetric.
- Cinques: no bluelines
- Royal: 17 bluelines, all symmetric.
- Caters: 7 bluelines, all symmetric.
- Major: 61 bluelines, all symmetric.
- Triples: 19 bluelines, all symmetric.
- Minor: 45 bluelines, all symmetric.
- Doubles: 22 bluelines, all symmetric.
- Minimus: 20 bluelines, all symmetric.
- Singles: 5 bluelines, 4 symmetric, and Shipping Forecast Singles on p18
(errors and omissions excepted)
) symmetric methods, it is saying the same thing as the 1998 Tower Handbook definition, and there was no particular reason to comment. …
But to be pedantic, that full stop between the sentences might have been better as a semicolon. And the last sentence is only worth saying about not-palindromic methods.
Then to 2018/2019: I wasn’t party to all the discussions during Framework development: it seems to me that the 2004 definition was carried-forward without analysing its probably-unintended ambiguity. Using the Framework definition has a not-palindromic method as “Double” with only (in the 1998-terminology) one axis of symmetry.
Sadly I could go on ...