Extents of Christ Church Dublin Differential Doubles

[John Schreiner <jeschreiner17 gmail com>]

Many thanks to our visitor Andrew introducing us to his home tower's
creation, Christ Church Dublin Differential Doubles.

We were wondering how calls work. Here is a possibility. Define a Section
End as the middle two blows of the 5 making long 5ths. In the plain course,
a 345 place is made at that point. If we define a Bob as a 125 place at the
SE, call a Bob at every other SE for an extent:

https://complib.org/composition/106074?accessKey=c6bdc192a32395604006d8211c27b790b2e4d075

Extents can be p-p-p- (p=Plain) or -p-p-p. It seems like they ought to be
just fine calling the 4 behind in a similar way, but I haven't figured out
how to convince Complib to show it yet.

John

ps. There are a variety of ways of looking at the method. I see it on the
page as upside-down Grandsire with the 4 and 5 trading places as the hunt
bells. This view was only a little bit helpful in the ringing, but hey, it
was still true. Here is the right-side-up version of the method that might
make the Grandsire comparison easier to see, 1 and 2 sharing the hunt work,
cheekily named Nilbud:

https://complib.org/method/47276?accessKey=00f73734d24430c1577b6f53b95e59f98633fd4c

Not to be confused with Notlob Little Surprise Major, which is another
thing entirely:

https://complib.org/method/21080

pps. It seems like the logical Triples extension of CCDDD would have the 6
and 7 trading off the long 7ths work, but the extensions found in Related
Methods don't work that way. Here is what I think the extension ought to 
be:

https://complib.org/method/47277?accessKey=8543cfca0692294be3506743257e1c943891093b
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