It is sometimes useful to be able to tie knots in the dark, or as in this video, behind your back
Step 4: Bowline on the Bight
A bowline "on the bight" is a bowline tied in a loop of rope (neither end is needed). The shape is the same as a bowline made with a double line, but the middle of the bight forms the loop around the standing part.
Uses: An impromptu bosun's chair - to sit in while being transferred between two boats at sea