De-wobbling Tables

Helen sent me this:

I'm not sure where this originated, so apologise for the lack of a reference. I'll happily update if someone can point me in the right direction! In the mean time I'll just link to the tweet I was sent.

I've heard this before: if you're suffering from a wobbly four-legged table don't mess around with trying to fold a napkin or stack beer mats to just the right thickness. Instead just turn the tables on that problem by... turning the table. Twist it around its own axis of symmetry and, within a quarter turn, you'll have a stable table.

There's a reason why this works and one of the places you can find out about that is in the Numberphile video embedded below: