How to create a folder named "con" or "aux" or "nul"

Have you ever tried to create a folder named "con" or "aux" or "nul" . if not then try now
can you do it directly ? of course not.

here is the way

step 1: Rename folder from the right click option
step 2: Now press alt and press 255.

step 3: press 255 frm the right side of the key bords i.e, Num pad.
          where only numbers are given.(means turning on numlock).
now write con and then press enter.
you ll see a con folder in ur pc