[r-t] in-course 120

[Andrew Johnson]

ringing-theory-bounces at bellringers.net wrote on 03/10/2006 20:40:01:

> Here is a little question I don't recall hearing about before:
> 
> Find an IN-COURSE 120 of (pure) doubles, in which each in-course row 
> occurs once at hand and once at back.  (Any such can of course be 
doubled 
> with a single to get a 240 with each row once at hand and once at back 
and 
> only two single changes).
> 
> I'm sure there are plenty of examples, but what about ones that can be 
> regarded as reasonably sensible methods?
> 
> Ander
> 
With a bit of experimentation I came up with
3.1.3.5.1.3.5.1.3.5.3.1.3.1.3.5.1.3.5.1.3.5.3.5

which has some nice symmetry.

Another way of using this method is to ring it to triples, e.g by 
replacing
the last change with '7' to give a principle of 168 changes, or replacing
the middle and last changes with '7' as required to make a touch.

Andrew Johnson