Reset Skew?

[alz]

There's an option to "Reset Skew" (right near "Reset Scale").

My interpretation of skew is to push or pull corners of the object in an independent direction. For example, taking a component cube and turning it into a trapezoid.

I can't find a way to actually skew the object though. Tugging on the scale handles keeps the object in its relative box shape.

What example would I need to be in to allow the "Reset Skew" option to function?