An Optical Illusion Bookshelf: Are There Three or Four Shelves?

Using inspiration from the impossible fork, ClarkeHopkinsClarke Architects built this optical illusion bookshelf. The shelf looks cartoony and almost invisible but that's not even the real illusion, the real mind bender is that there are what seems like 4 shelves on the left side but only 3 shelves on the right side. Whoa. [Neatorama]

An Optical Illusion Bookshelf: Are There Three or Four Shelves?

That's three shelves on the right side

An Optical Illusion Bookshelf: Are There Three or Four Shelves?

But four shelves on the left side