Box Trace: The <b>box trace</b> can help you understand how a recursive call works.
<ul>
	<li>	Label each recursive call in the body of the recursive method.</li>
	<li>Represent each call to the method by a new box in which you note the method’s local environment. Each box will contain:
	<ul>
		<li>	The values of the references and primitive types of the method’s arguments.
		<li>	The method’s local variables
		<li>	A placeholder for the value returned by each recursive call from the current box.
		<li>	The value of the method itself.
		<li>	When you first create a box, you will know only the values of the input arguments.  Fill in the values of the other items as you determine them from the method’s execution.
	</ul>
	<li>	Draw an arrow from the statement that initiates the recursive process to the first box.
	<li>	After you create the new box and arrow, start executing them body of the method.
	<li>	On exiting the method, cross off the current box and follow its arrow back to the box that called the method. 
</ul>
<img src="http://homepages.uc.edu/~jonesbr/content/boxtrace.gif">