322: Mainline

Here is a look at the four method evaluations performed when 3 is the receiver of the recursivePowerOfTwo method:

Receivers      |     ^      Answers 
            3  v     |  8   
           *---------------------* 
           | recursivePowerOfTwo | 
           *---------------------* 
               |     ^    
            2  v     |  4  
           *---------------------* 
           | recursivePowerOfTwo | 
           *---------------------* 
               |     ^    
            1  v     |  2  
           *---------------------* 
           | recursivePowerOfTwo | 
           *---------------------* 
               |     ^    
            0  v     |  1  
           *---------------------* 
           | recursivePowerOfTwo | 
           *---------------------*