This is very interesting and I plan to do a piece on the wall in my apartment. I've previously done some Varini pieces in another apartment out of tape: http://www.varini.org/02indc/indgen.html

My favorite part is in the Mona Lisa: look at her left eye, close to the screen, noticing the slight variation in stroke size, and then quickly squint.

That's brilliant! Another hack: vary your distance from the screen, moving really close up to the picture, and then back away, till you're leaning back in your chair.

> and then quickly squint.

Is something surprising supposed to happen when you do that? Doesn't for me...

Wow the squinting really works well! It is like a magic eye, except I can actually see it!

The version of the Mona Lisa in particular is doing interesting things to my brain. Usually the tendency to perceive faces is so strong that you see them with the slightest encouragement. But when I look at this there is some other hard-wired tendency-- perhaps a tendency to follow lines-- that's fighting with the tendency to perceive faces.

Someone explained the appeal of Picasso's cubist faces in a similar way: it is a hack that triggers higher response from our face detectors than a normal face would.

Here is an explanation of a simple algorithm that can generate those images, plus a Mathematica program that generates them: http://hernan.moraldo.com.ar/mazegeneration.htm

Here are some more examples:

http://www.oberlin.edu/math/faculty/bosch/tspart-page.html

This would be a nice iPhone app

Of course, it would take NP-forever