[Retros] rights & ocassions / not answering Andrew anymore

[Retros Probleemblad]

On 05/24/2014 02:40 PM, Nicolas Dupont wrote:

> By the way, is it possible to construct a sound PG with a repetition of
> the diagram position? Of course, if any, it cannot be a SPG.

Impossible, I think. If the repetition is in an even number of moves 
(2M), you can just add M times Sa3 Sa6 Sb1 Sb8 at the beginning. And any 
moves that will free another piece than a knight will allow an odd 
number of moves resulting in a switchback.

Joost