% Trace of PROPS run on kinship rules in kinship.pl. 

> /opt/local/bin/swipl
Welcome to SWI-Prolog (Multi-threaded, 64 bits, Version 6.4.1)
Copyright (c) 1990-2013 University of Amsterdam, VU Amsterdam
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For help, use ?- help(Topic). or ?- apropos(Word).

?- consult(props).
% props compiled 0.00 sec, 52 clauses
true.

?- consult(kinship).
% kinship compiled 0.00 sec, 7 clauses
true.

?- show_wm.
--------
Working Memory:
* parent(abe,bob)
* male(abe)
* parent(bob,dan)
* male(bob)

true.

?- run(5).
--------
Working Memory:
* parent(abe,bob)
* male(abe)
* parent(bob,dan)
* male(bob)

Cycle 1
Firing:  father
--------
Cycle 2
Firing:  father
--------
Cycle 3
Firing:  grandfather
--------
true.

?- show_wm.
--------
Working Memory:
* parent(abe,bob)
* male(abe)
* parent(bob,dan)
* male(bob)
* father(abe,bob)
* father(bob,dan)
* grandfather(abe,dan)

true.

?- halt.
>