The Most Epic Book of Maths Ever demonstrates the chess board illusion. If the rows of black and white squares are moved along a bit, it gives the impression that the lines dividing the rows are not parallel!
Here's how it appears in the book:
The illusion was first spotted on tiled surfaces.
One of the most famous examples in the world is the cafe wall at the bottom of St Michael's Hill, in Bristol, England. Sadly the tiles are rather worn and cracked, but the illusion is still there!
Here's another version of the same trick. None of the lines in this image are curved!
There are lots of important factors to make this work. If you look at the same picture but on a bigger scale, is it as good?
The colours used, the thickness of the
By the way ...