Function to print a diamond shape

[Ali Çehreli]

This is a somewhat common little exercise: Write a function that takes 
the size of a diamond and produces a diamond of that size.

When printed, here is the output for size 11:
     *
    ***
   *****
  *******
 *********
***********
 *********
  *******
   *****
    ***
     *

What interesting, boring, efficient, slow, etc. ways are there?

Ali