[r-t] Extension of TDMMs

[Richard Smith]

On Sunday, PABS reminded me that I'd promised to show him a
method extension that works on three different stages but
does not cover an arbitrary number of stages.  This sounds
like a suitably arcane topic for the new list!

Warkworth Surprise Minor with a mode-3 BC extension above a
mode-1 EF extension gives the following surprise major
and royal methods.

  &-36-6-256-36.4-2.5.6-4.5,1
  &-38-8-258-38.4.78.2.58.6-4.7.8-6.7,1

At higher stages, however, you always get irregular lead
ends (which are frequently differential hunters).

So much for the idea that an extension that covers three
stages will cover an indefinite number!  Now, can anyone
find an extension that covers a larger number of stages
without covering a indefinite number?

Richard