Lists and Dictionaries:
The elements of a list are indexed numerically, whereas a dictionary stores its data based on key/value pairs. In our lsystems, for instance, a key would be a symbol and a value would be a replacement symbol. The dictionary is appropriate for this project because instead of a searching through a list for the proper rule, you can use the key to access the replacement rule immediately.
To create my final scene, I imported my zturtle, lsystem3, and city2 files. This way, I was able to work with both turtle and zelle graphics, use the Lsystem class to generate the designs using lsystems, and use my buildings from project 6. I created 3 different lsystems, one of which with 2 possible rules. I appended each of these to a list (systems), and then used a for loop to go through each lsystem and draw each tree, changing the x-axis value each time through. This loop cut down on code and made it easier to move the trees around my image until I was satisfied with it.
Here are my lsystems:
( 'F', [['F', 'fF[+FR-]F[-F+][+FL][FO]'] ], 4, 22.5, 5 )
( 'F', [['F', 'FR[+FL]FL[-FO]F'], ['F', 'F', 'fF[+FR-]F[-FG+][+FL][FB]']], 4, 23, 4 )
( 'F', [['F', 'fF[+FR-]F[-FG+][+FL][FB]']], 4, 26.2, 3.8 )
Here's the final scene: