For example, here's a hell of popup windows flying around the screen, following
my cursor.
This is built with CSS anchor positioning, only the red popup follows my mouse
and all of the other ones are indirectly linked to it via a chain of anchors.
This was a great way to learn how the feature works, and allowed me to demo it
quite nicely for others.
But, in doing this, I hit a bug. This demo used to crash Firefox quite badly. So
I filed the bug and it later got fixed.