Editing L-system (section)

===Example 5: Sierpinski triangle===
The [[Sierpinski triangle]] drawn using an L-system.

:     '''variables''' :   F G
:     '''constants''' :   + &minus;
:     '''start'''     :   F&minus;G&minus;G
:     '''rules'''     :   (F → F&minus;G+F+G&minus;F), (G → GG)
:     '''angle'''     :   120°

Here, F and G both mean "draw forward", + means "turn left by angle", and &minus; means "turn right by angle".

<gallery mode="nolines" widths="256px" heights="256px">
File:Sierpinski Triangle (from L-System, 2 iterations).png|n = 2
File:Sierpinski Triangle (from L-System, 4 iterations).png|n = 4
File:Sierpinski Triangle (from L-System, 6 iterations).png|n = 6
</gallery>

It is also possible to approximate the [[Sierpinski triangle]] using a [[Sierpiński arrowhead curve]] L-system.

:     '''variables''' :   A B
:     '''constants''' :   + &minus;
:     '''start'''     :   A
:     '''rules'''     :   (A → B&minus;A&minus;B), (B → A+B+A)
:     '''angle'''     :   60°

Here, A and B both mean "draw forward", + means "turn left by angle", and &minus; means "turn right by angle" (see [[turtle graphics]]).

[[File:Serpinski Lsystem.svg|centre]]
{{center|1=Evolution for ''n'' = 2, ''n'' = 4, ''n'' = 6, ''n'' = 8}}