Drawing a pierced rectangle facet

[Jens Simon]

Hallo Samuel, 
thank you for posting your code. I like it more than mine in the 2D case.

However - the origin of my question is 3D. I have written a modest "toolbox"
with 3D-elements like cylinder, pineapple slice, sphere, cuboid and pierced
cuboid using plot3d2. The toolbox is to allow simple 3D drawings which can be
zoomed and rotated.

To facilitate communication in my post I reduced it to 2D - which was misleading
in this case instead of easing, sorry.

So I have to stay with my somewhat complicated plot3d2 approach.

Kind regards
Jens