It’s Just An Illusion
So it turns out, the lines are actually straight. Crazy right? They look so crooked. This is known as a Café Wall Illusion, where black and white staggered tiles look crooked to the naked eye. Interesting, right?
Initially, when this was first discovered in 1898, it was known as “The Kindergarten Illusion”. However, in 1973 a guy named Richard Gregory renamed it “The Café Wall Illusion”. The effect was observed by his laboratory member, Steve Simpson who noticed the tiles on a café wall at the bottom of St Michael’s Hill, Bristol. It is also a variant on the chessboard illusion by Hugo Munsterberg.