Optical Illusion

Everyone I was browsing the web looking up optical illusion art, you all have to check this work of art out and tell me what you guys think. At first I thought this was a graffiti artist. His style, technique, and even the medium used are so different. There is a person on youtube who stated that this is not an optical illusion but only perspective/atmospheric perspective manipulation. He and I have been going at one another about this work of art. Please tell me what you all think of this..