set(binary_resolution).
clear(print_initial_clauses).
clear(print_kept).
clear(print_given).
assign(max_seconds,1).
assign(stats,none).

formulas(sos).

% Some square has a wumpus.
exists x (wumpus(x)).

% If one square has a wumpus, other squares don't.
wumpus(x) & -(x=y) -> -wumpus(y).
 
end_of_list.

formulas(goals).

% I want to prove that there is some square such
% that all other squares have no wumpus
exists x all y (x=y | -wumpus(y)).

end_of_list.