Drachenkurven II

Dragon.om

PROCEDURE Dragon(graphic: TurtleGraphics.Graphic; level: INTEGER); (* Dragon curve (X -> X+YF+, Y -> -FX-Y) *) PROCEDURE Left; BEGIN TurtleGraphics.Left(graphic); END Left; PROCEDURE Right; BEGIN TurtleGraphics.Right(graphic); END Right; PROCEDURE Forward; BEGIN TurtleGraphics.Forward(graphic); END Forward; PROCEDURE ^ Y(n: INTEGER); PROCEDURE X(n: INTEGER); BEGIN IF n > 0 THEN X(n-1); Left; Y(n-1); Forward; Left; END; END X; PROCEDURE Y(n: INTEGER); BEGIN IF n > 0 THEN Right; Forward; X(n-1); Right; Y(n-1); END; END Y; BEGIN Forward; X(level); END Dragon;