I saw this today in a blog post:
It's obviously visually astonishing, and my first thought was that it
would make a great sample in inkscape, although perhaps not distributed
Unfortunately, I'm not yet able to make the basic perspective shapes in
inkscape, much less the convincing visual illusion of shadow.
If any expert inkscape user with good perspective-, alpha- and gradient-fu
wanted to try this one, it would make a one humdinger of a tutorial.