[r-t] Spliced doubles (was triples)

Philip Earis pje24 at cantab.net
Mon Jul 20 10:07:27 UTC 2015

```Mark: "The composition, as written, perhaps does not indicate clearly enough
that a block starting, for example, 'SS' (Stedman Slow) tells the band to
ring Stedman starting with a slow six (which, with no change of method, will
then be followed by a quick six, slow six, quick six etc)"

Aha.  I would agree that describing the composition a bit less ambiguously

Me: "Can someone put together an analogous 120 of doubles, eg with 2, 4, 6
change blocks?"

OK, I am answering my own question here.

I wanted to put something together that was as simple as possible, with
symmetric, basic blocks (rather than replicating the triples to include
blocks of Carter etc), so that a band might be able to ring it even without
the luxury of Mr Eccleston conducting.  I therefore started with the
following design criteria:

- Maximal number of pure doubles changes
- Maximal number plain leads of blocks, and calls only in one type of block
if possible
- Inclusion at a minimum of Original, Stedman six, and the beautiful grid
generated by the block 5.3.1.3 (ie Saturn doubles, but rotated to start with
the 5 notation in common with all other blocks in the composition, as per
the triples. It's a wonderful fun method that should be much more common -
try it, folks!)

To satisfy these criteria, I starting looking at in-course extents of
doubles (ie 60 changes) as a base. There are 44 of these if you strip out
rotations & reversals...Richard Smith had previously generated a list that
can be seen at
<http://ex-parrot.com/~richard/doubles/extents/half-extents.txt>

After a bit of inspection and playing around, I rotated number 20 on the
list and divided it accordingly to produce what I think is a rather nice 120
of spliced:

===
60 Spliced Doubles (4m)

12345
Original   34512  pppbbp
Sted Q     34125  p
Original   51423  bpp
Saturn8    32541  p
Original   32415  b
Saturn8    51342  p
RTitanic   24531  pp
Original   24315  b
RTitanic   12453  p
Original   12345  bb

Repeat for 120, calling single halfway and end.

The only bobs are in Original (3 instead of 1)

Original = 5.1 (2 changes)
R Titanic = 5.1.3.1 (4 changes)
Stedman Quick = 5.1.3.1.3.1 (6 changes)
Saturn8 = 5.3.1.3.5.3.1.3 (8 changes)
===

There's lots of scope for fun here.  What else can people put together?

(Incidentally, short symmetric doubles blocks are of course likely to give
very elegant lines. I also like the six-change block 5.1.3.1.5.3)

```