=================================================================
Logtalk - Object oriented extension to Prolog
Release 2.17.1
Copyright (c) 1998-2004 Paulo Moura. All Rights Reserved.
| ?- square::nsides(N).
N = 4
yes
| ?- square::area(A).
A = 1
| ?- q1::(color(Color), side(Side), position(X, Y)).
Color = red
Side = 1
X = 0
Y = 0
| ?- q2::(side(Side), area(Area), perimeter(Perimeter)).
Side = 3
Area = 9
Perimeter = 12
