[r-t] Lead-based methods [was: Poll on consecutive blows in the same position]

[Mark Davies]

Don writes,

> A β-method is an α-method that when applied to any of the N! possible
> starting rows always results in the same sequence of changes.

Yes, this is helpful.

And, given the wild variation possible with non-α (stochastic) or non-β 
(what I previously called rule-based) methods, I vote we stick with the 
comparatively easy β class. These I believe can be defined using their 
lead, a fixed sequence of changes.

Can we have a vote - who agrees we should focus on the β methods? 
(Implicitly we have been doing so, up to now, anyway).

MBD