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:


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


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: