Draw Unique pattern with javascript / php / C++

Can someone help me for draw the following unique pattern function using php or javascript assumed function name is createpattern($n) with $n = integer ;

so 1.Call createpattern(1) it will draw :

    x

2.Call createpattern(2) it will draw :

   x
  x x
   x

3.Call createpattern(3) it will draw :

  x
 x
x o x
   x
  x

4.Call createpattern(4) it will draw :

   x
  x
 x o 
x o o x
   o x
    x
   x

5.Call createpattern(5) it will draw :

         x
        x
       x o
      x o
     x o x o x
          o x
         o x
          x
         x

so on ...

it's very unique pattern so i can't solved it.