Hollow Mask

Now I know that I do not suffer from schizophrenia (人格分裂） :D

Randomly came across this test where a constant moving mask is presented.



It's mentioned that if you can see the concave face, that means .... high possibility that you're a schizophrenic. Otherwise, safe.



If you are mentally healthy, every each of the image above should appear convex.

So, can you see the hollow mask??