When I was young, my dad taught me how to tie an extension cord into a chain knot. He's an electrician, owns his own business, and chain knots are a good way to keep the cords from getting tangled on job sites.
This image is from a Humburg home movie, when they were rebuilding their house from the Andover tornado in 1991. It's Burt's late father, showing him how to tie an extension cord into a chain knot.
Gotta admit, that gave me a little chill.