These photos show rooms painted in such a way that, if you stand in the correct place, a pattern will appear. Despite looking photoshopped, they are real. The painted rooms are the creations of artist Felice Varini. On his website you can find more examples of his art if you search around long enough (and struggle through the incredibly bad navigation). Varini writes:

The painted form achieves its coherence when the viewer stands at the vantage point. When he* moves out of it, the work meets with space generating infinite vantage points on the form. It is not therefore through this original vantage point that I see the work achieved; it takes place in the set of vantage points the viewer can have on it. If I establish a particular relation to architectural features that influence the installation shape, my work still preserves its independence whatever architectural spaces I encounter. I start from an actual situation to construct my painting. Reality is never altered, erased or modified, it interests and seduces me in all its complexity. I work "here and now".

I have no idea what that's supposed to mean, but the illusions are pretty cool. (Thanks to Eric Kimlinger for sending me a link to the photos.)