Calling J from Python

[greg]

Alexander Schmolck wrote:
> how would you code a program that gives the following
> output ('skewed' sierpinski-triangle) in python?
> 
> 
> *               
> **              
> * *             
> ****            
> *   *           
> **  **          
> * * * *         
> ********        
> *       *       
> **      **      
> * *     * *     
> ****    ****    
> *   *   *   *   
> **  **  **  **  
> * * * * * * * * 
> ****************

###############################################################

def print_sierpinski(order):
     size = 4 * 2 ** order
     buffer = [size * [" "] for i in range(size)]
     put_sierpinski(buffer, size, 0, 0)
     for line in buffer:
         print "".join(line)

def put_sierpinski(buffer, size, x, y):
     if size == 4:
         put_triangle(buffer, size, x, y)
     else:
         size2 = size / 2
         put_sierpinski(buffer, size2, x, y)
         put_sierpinski(buffer, size2, x, y + size2)
         put_sierpinski(buffer, size2, x + size2, y + size2)

def put_triangle(buffer, size, x, y):
     for i in range(3):
         buffer[y + i][x] = buffer[y + i][x + i] = "*"
     for i in range(4):
         buffer[y + 3][x + i] = "*"

print_sierpinski(2)

###############################################################

By making the recursion explicit, I think this brings out the
self-similarity better than any of the other solutions posted,
which are very clever but not what I would call "lucid".

--
Greg