L-Systems can be used to draw plants! To make this work, we need to add some capabilities to our Turtle structure. Up until now turtles could either move ahead or turn. To draw plants, we need to be able to save a turtle state, do some drawing, and then move the turtle back to the saved state. This has the effect of magically teleporting the turtle to someplace it has already been, restoring its position, direction and color.
Let’s look at L-Systems ! Also known as Lindenmayer Systems, after their inventor, Aristid Lindenmayer , L-Systems are sets of rules for manipulating symbols. They consist of an alphabet of symbols that can be used to make strings, and a set of rules used to transform those strings. When fed a starting string, it will produce a sequence of new strings based on its rules. This was originally a way to formally describe the growth of fungi, algae, etc.
Turtle graphics are a form of vector graphics. In its most basic form, there is an object that moves around the canvas, leaving a trail as it goes. It’s called turtle graphics because you can think of the object as turtle with a pen strapped to her shell. The turtle can do two things: 1) move in a straight line for a certain distance, and 2) rotate to face a new direction.