Exercise 2. Schelling's Tipping Model, continued.  The purpose 
of this exercise is to study some of the effects of having unequal 
numbers of the two types of actors.  You should use the variant of 
Schelling's model described in the first exercise.  The exercise is to 
answer these two questions and explain why things worked out as 
they did:
- Do minorities get packed in tighter than majorities? 
 - Does the process settle down faster when the numbers 
are unequal?
 
	To make things concrete, use 30 Whites and 10 Blacks, both 
with the original (and equal) requirements for contentment.  For 
density studies, use the A and B measures described for the first 
exercise.
	Your should arrange to stop a run when no further change is 
possible.  An easy way to do this is use periods of at least 40 
events, and check whether there has been no movement in the 
current period since that would imply that everyone is content and 
no will ever move again.  As in the first exercise, a beginner may 
choose to use the source code provided, and make the necessary 
changes.