% Francois Labelle & computer, January 30, 2004
% All 3 checkmate PG-2.5 with exactly 1 solution.
% They are all SPGs.

% Comment:
%
% SPG #1 is attributed to Juha M. Saukkola
% SPG #3 is attributed to Joost de Heer and Richard Stanley
% SPG #2 is a simple variant of #3


(Forsyth-Edwards Notation, followed by the same list in ascii diagrams)

SPG-2.5:

rnbqkbnr/ppppp2p/8/5PpQ/8/8/PPPP1PPP/RNB1KBNR
rnbq1bnr/ppppkppp/8/4Q3/8/4P3/PPPP1PPP/RNB1KBNR
rnbq1bnr/ppppkppp/8/4Q3/4P3/8/PPPP1PPP/RNB1KBNR

 _________________ _________________ _________________ 
|                 |                 |                 |
| r n b q k b n r | r n b q . b n r | r n b q . b n r |
| p p p p p . . p | p p p p k p p p | p p p p k p p p |
| . . . . . . . . | . . . . . . . . | . . . . . . . . |
| . . . . . P p Q | . . . . Q . . . | . . . . Q . . . |
| . . . . . . . . | . . . . . . . . | . . . . P . . . |
| . . . . . . . . | . . . . P . . . | . . . . . . . . |
| P P P P . P P P | P P P P . P P P | P P P P . P P P |
| R N B . K B N R | R N B . K B N R | R N B . K B N R |
|_________________|_________________|_________________|