Depending on where you live Twix packaging has an end like this, which gives you a top of the package to orient yourself to. But that’s besides the point because the ad expects you to not think about it too hard and just accept a left and right twix.
But that can’t be the joke because there is no inherent orientation to twix bars, so there cannot be a “left”
The wrapper is not symmetrical. You can consistently define a left and right bar of a given Twix in an unambiguous way.
Depending on where you live Twix packaging has an end like this, which gives you a top of the package to orient yourself to. But that’s besides the point because the ad expects you to not think about it too hard and just accept a left and right twix.