S&W, page 158, exercise 1.5.26:

Write a program Circles that draw filled circles
of random size at random positions within the unit
square.  Your program should have four main variables:
<ol>
<li> N (number of circles)
<li> min (min radius of a circle)
<li> max (max radious of a circle)
<li> prob (probability a circle is filled black.  Note, if not black, then white)
</ol>

Run your program for different cobinations of values for the 4 main variables.