L-systems are a different type of grammar than the formal language grammars in an automata theory course, so they are good for students to see their geometric interpretation and their different rules for evaluation. In this lesson we start by defining the L-systems formally, and then using JFLAP to work through several examples that incrementally get more complicated. The lesson then concludes with three exercises for students to try with JFLAP. We also usually follow up with an assignment and contest in which students submit an L-system they create and the students vote on them.