Better video via the link I submitted a year ago: http://news.ycombinator.com/item?id=468063

This item has also shown up several times before:

http://searchyc.com/shoelace

It's one of the methods I use to assess how to present things:

http://news.ycombinator.com/item?id=1059659

It lets me know if someone will like puzzles for their own sake, or if "everything has to have a use."