After lines, angles are the most important in the creation of patterns in an L system. The following are a few examples of what differences in angles look like, based on the default state of the Explorer.

In all of these examples, clicking on the associated image will take you to the explorer, pre-configured to generate that image.

This is the initial condition, with an angle between lines of 90°:

Changing the angle to 60° results in this:

…And here is 45°:

Increasing past 90° makes the pattern more compact. Setting the angle to 120° creates a triangle pattern:

Increasing the iterations with the 120° pattern results in larger sets of nested triangles:

And finally, increasing the angle to 270° effective creates a mirror image of a pattern created with a 90° angle:

These should give you enough starting points to begin creating some interesting patterns. The angles which don’t precisely divide into 360 can result in some interesting interference patterns in the overlapping lines.