overhand knot (thing)

This is a basic stopper knot, to keep a rope from going through a hole or to reduce fraying at the end of a rope; however, the figure eight knot works better for that. Overhand knots are interesting mostly because they form the basis for many other knots:

• square knots are two overhand knots, executed as mirror images (right over left, then left over right; or vice-versa);
• granny knots are usually the result of screwing up the aforementioned square knot (two overhand knots tied the same way);
• shoelace knots start with an overhand knot.

In ASCII art, an overhand knot tied on a single rope looks much like a pretzel:

           ______  ______
          /      \/      \
         /   __   \  __   \
        /   /  \   \/  \   \
        \   \  /\   \  /   /
         \   \/  \   \/   /
          \  /   /\  /   /
           \/   /  \/   /
___________/   /\__/   /\______
              /       /        |
_____________/\______/\________|

Topologically equivalent, but a bit weirder looking:

           ______________________
          /                      \
         /   __________________   \
        |   /                  \   |
        |   \  ______  ______  /   |
         \   \/      \/      \/   /
          \   \  __   \  __   \  /
           \   \/  \   \/  \   \/
___________/\   \__/\   \__/\   \____
             \       \       \       |
_____________/\______/\______/\______|

When tied with two ends (as you would if you were using it as the start of a larger knot), it looks like this:

                (make bow here)

          \   \  ______  ______  /   /
           \   \/      \/      \/   /
            \   \  __   \  __   \  /
             \   \/  \   \/  \   \/
  ___________/\   \__/\   \__/\   \__________
               \       \       \     
  _____________/\______/\______/\____________