Nagai Hideyuki uses two sketchbooks to create illusions. I was thinking this may be possible to do on the street/buildings with chalk, but in order to view it correctly everyone would have to be the same height, so that probably wouldn't work.
A delicious fuck-ton of human knee references. Yeah, just a quick mention of one of the above images… there’s a cyst on one of those muscular diagrams… don’t… don’t include the cyst in normal anatomy. But, yeah. Just thought it.