a blog by keith calder, a film and television producer

Why shoelaces come untied when we walk?

I love everything about this academic paper on the roles of impact and inertia in the failure of a shoelace knot. In particular, I love this footnote:

The speed of the knot failure brings to mind a Hemingway line from The Sun Also Rises describing a character's descent into bankruptcy—which here we found to be an apropos description of knot failure—it happens ‘Two ways. Gradually, then suddenly.’