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Task/Sierpinski-triangle-Graphical/Prolog/sierpinski-triangle-graphical-1.pro

@@ -0,0 +1,30 @@
+sierpinski(N) :-
+	sformat(A, 'Sierpinski order ~w', [N]),
+	new(D, picture(A)),
+	draw_Sierpinski(D, N, point(350,50), 600),
+	send(D, size, size(690,690)),
+	send(D, open).
+
+draw_Sierpinski(Window, 1, point(X, Y), Len) :-
+	X1 is X - round(Len/2),
+	X2 is X + round(Len/2),
+	Y1 is Y + Len * sqrt(3) / 2,
+	send(Window, display, new(Pa, path)),
+        (
+	   send(Pa, append, point(X, Y)),
+	   send(Pa, append, point(X1, Y1)),
+	   send(Pa, append, point(X2, Y1)),
+	   send(Pa, closed, @on),
+	   send(Pa, fill_pattern,  colour(@default, 0, 0, 0))
+	).
+
+
+draw_Sierpinski(Window, N, point(X, Y), Len) :-
+	Len1 is round(Len/2),
+	X1 is X - round(Len/4),
+	X2 is X + round(Len/4),
+	Y1 is Y + Len * sqrt(3) / 4,
+	N1 is N - 1,
+	draw_Sierpinski(Window, N1, point(X, Y), Len1),
+	draw_Sierpinski(Window, N1, point(X1, Y1), Len1),
+	draw_Sierpinski(Window, N1, point(X2, Y1), Len1).

Task/Sierpinski-triangle-Graphical/Prolog/sierpinski-triangle-graphical-2.pro

@@ -0,0 +1,40 @@
+:- dynamic top/1.
+
+sierpinski_iterate(N) :-
+	retractall(top(_)),
+	sformat(A, 'Sierpinski order ~w', [N]),
+	new(D, picture(A)),
+	draw_Sierpinski_iterate(D, N, point(550, 50)),
+	send(D, open).
+
+draw_Sierpinski_iterate(Window, N, point(X,Y)) :-
+	assert(top([point(X,Y)])),
+	NbTours is 2 ** (N  - 1),
+	% Size is given here to preserve the "small" triangles when N is big
+	Len is 10,
+	forall(between(1, NbTours, _I),
+	       (   retract(top(Lst)),
+		   assert(top([])),
+		   forall(member(P, Lst),
+			  draw_Sierpinski(Window, P, Len)))).
+
+draw_Sierpinski(Window, point(X, Y), Len) :-
+	X1 is X - round(Len/2),
+	X2 is X + round(Len/2),
+	Y1 is Y + round(Len * sqrt(3) / 2),
+	send(Window, display, new(Pa, path)),
+        (
+	   send(Pa, append, point(X, Y)),
+	   send(Pa, append, point(X1, Y1)),
+	   send(Pa, append, point(X2, Y1)),
+	   send(Pa, closed, @on),
+	   send(Pa, fill_pattern,  colour(@default, 0, 0, 0))
+	),
+	retract(top(Lst)),
+	(   member(point(X1, Y1), Lst) -> select(point(X1,Y1), Lst, Lst1)
+	;   Lst1 = [point(X1, Y1)|Lst]),
+
+	(   member(point(X2, Y1), Lst1) -> select(point(X2,Y1), Lst1, Lst2)
+	;   Lst2 = [point(X2, Y1)|Lst1]),
+
+	assert(top(Lst2)).