The hollow Einstein face

We have an illusion that consists of a hollow face of Einstein which seems to be looking at you whether you are looking at the front of it or the back. It’s very impressive. I use it to remind students (and myself) that there is a heck of a lot out there that we still don’t understand, even if we like to pretend otherwise.
The illusion can be purchased from, one of the very best sources for all types of illusions.

So when New-Scientist posted a video on how this was being used to test for schizophrenia, I thought perhaps it was time to check it out again (apparently people suffering from schizophrenia don’t notice the effect).