I would like to find some images in which there are logical inconsistencies. I want to use them for practicing my attention towards those kinds of logical errors (so that I could more easily spot them in my dreams, I am not sure if this works, but I just want to test.). I remember back in the high school someone showed me a picture where one is supposed to find such logical inconsistencies and picture included shadows facing wrong directions, things affected by winds in different directions etc.
The University of Adelaide has a lot of information concerning inconsistent images:
There are also a few of those on this page: