The padlock knot is designed to look like a padlock, but without the actual function of one. In order to tie this knot take your rope or string and fold it in half. After you have done that make a loop with both sides of the rope making sure you leave a loop at the top. Put the two loops together the one in the front turning clockwise and the one in the back counter-clockwise. Make sure to leave a hole in the center for the rope to pass through. Now wind each piece of rope through the hole in the center. The amount of times you wind it depends on the size of knot you want. Make sure to pull it fairly tight while winding. When you have reached the desired size you can trim the ends to give it a more appealing look.