% In Elementary Pascal Ledgard & Singer have Sherlock Holmes program
% the Analytical Engine to confirm the identity of the murderer of
% a well known art dealer at the Metropolitan Club in London.
% The murderer can be deduced from the following apparently trivial
% clues.
:-op(50, xfx, wore).
:-op(50, xfx, has).
:-op(50, xfx, was_in).
:-op(40, xf, hair).
mr_holman wore  a_ring.
mr_pope wore  a_watch.
mr_woodley wore pincenez:-sir_raymond wore tattered_cuffs.
sir_raymond wore pincenez:-mr_woodley wore tattered_cuffs.
X wore tattered_cuffs:-X was_in room_16.

X has black hair:-X was_in room_14.
X has brown hair:-X wore pincenez.
X has grey hair:-X was_in room_12.
X has red hair:-X wore tattered_cuffs.

murderer(X):-X has brown hair.

mr_holman was_in room_12.
sir_raymond was_in room_10.
mr_woodley was_in room_16.
X was_in room_14:-X wore  a_watch.

:- write('The game is afoot....'), nl.