@o draws a 2 dimensional disk in the z=0 plane. The diameter is determined by the turtle parameter line width and the position of the origin is determined by the current x and y coordinates of the turtle.

@c draws a 2 dimensional disk in the plane defined by the turtle's heading vector and left vector (see Figure 2.1). The diameter is determined by the turtle parameter line width and the position of the origin is determined by the current x and y coordinates of the turtle.

@O draws a 3 dimensional sphere. The diameter is determined by the turtle parameter line width and the position of the origin is determined by the current x and y coordinates of the turtle.

Example: The following production draws a smaller sphere connected to a larger sphere by a straight line. Lsystem: 0 derivation length: 1 Axiom:X homomorphism X --> @O(2)F(6)@O(3) endlsystem

Example: The following L-System produces a two dimensional picture consisting of a circle surrounded by a spiral. #define da 0.25 Lsystem: 0 derivation length: 1440 Axiom: X(0) X(a) --> A(a)X(a+da) homomorphism A(a) --> [+(a)f(1)@o(0.1)+(3*a)f(0.5);@o(0.1)] endlsystem

Example: The following L-System draws a molecule with four atoms connected to the center of the molecule. #define STEPS 3 #define TET 70.5 /* 180 - 109.5 */ #define C_SIZE 0.6 #define H_SIZE 0.5 Lsystem: 0 derivation length: STEPS Axiom: ,(1)#(0.15)|X X --> HFC[^(TET)FH]/(120)[^(TET)FH]/(120)[^(TET)FH] C --> [,(2)@O(C_SIZE)] H --> [,(3)@O(H_SIZE)] endlsystem

					Preface Parameters Appendix I Appendix II References
Index	Circles and Spheres	Generalized Cylinders	Surfaces	Textures