Hello there,
I've been working recently on the inclusion of Truchet-like patterns into the filter
Patterns / Op-Art available in the G'MIC plug-in for GIMP.
What I wanted to do is generating Truchet patterns that can be placed randomly (and rotated) without visible seams (so an usual Truchet pattern

),
but at the same time, some of them should have slight differences so that they can make the impression of encoding a luminance of each pixel of an input image.
What I've ended up with is a code that generates a family of more or less eroded/dilated Truchet patterns (but all seamless together, they join perfectly).
And then, I've added them to the filter. I've also added a general
Allow angle option, so that any selected pattern can be randomly rotated by the Op-Art filter if needed.
At the end, it looks like this (go far from the screen to get a better illusion !)
Attachment:
truchet_illusion.jpg [ 407.42 KiB | Viewed 5576 times ]
So, Lyle, what do you think about it ? :p
You can already play with this new toy, by updating your filters (requires 1.5.8.0+ by the way).