An optical illusion which shows a series of spinning black and white crosses has prompted a level of online bewilderment not seen since #TheDress.

As with its viral predecessor, the question at the heart of this illusion is about colour: in this case, is the background black or white?

There doesn’t appear to be a correct answer. In fact, some people have questioned whether the image even has a background.

The white crosses spin clockwise before the black crosses spin anticlockwise, forming a moving image confusing enough to give Redditors headaches.

The image, which has been viewed over 4 million times on Imgur, was first spotted by Digg, who suggested it’s based on “figure-ground organisation”.

The term was coined in 1915 by Edgar Rubin, a psychologist who created the eponymous Rubin’s vase, an image showing two heads and a vase.

While it’s possible to see both the heads and the vase almost at once, the mind tends to focus on one or the other at the start – just as we tend to either see the black or white spinning crosses first in this illusion.

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