Friday October 19

1. Finish the butterfly model so that it has the features described in Section
5.5:

It reads in the real landscape and sets the patch colors according to their
elevation.

The butterflies do not stop when they reach a hilltop. Instead, they keep moving
for 1000 ticks.

The butterflies start randomly within a small patch.

2. Make a new version of the model that allows users to restart the simulation,
using the same landscape without having to read in the data file again.

3. Make a final version of the model that performs the analysis described in
Exercise 6. on p. 72. You can use whatever measure of clumping you think is
appropriate.

Be prepared to demonstrate your models in class on Friday.