348: Mainline

Here is a look at the four calls involved when the recursive_power_of_2 function is set to work on 3:

Arguments      |     ^      Returned values 
            3  |     |  8   
               v     | 
           *-------------* 
           | First call  | 
           *-------------* 
               |     ^    
            2  |     |  4  
               v     | 
           *-------------* 
           | Second call | 
           *-------------* 
               |     ^    
            1  |     |  2  
               v     | 
           *-------------* 
           | Third call  | 
           *-------------* 
               |     ^    
            0  |     |  1  
               v     | 
           *-------------* 
           | Fourth call | 
           *-------------*