Back in February 2015, the whole word was asking itself: blue and black or white and gold?
For a couple of days, it was all about 'the dress'.
Well, just when you thought it was safe to go back on Twitter, it seems it's happening all over again - this time with a pair of flip flops.
On Thursday night, Falsiane, a Portuguese Twitter account, posted a photo taken in a shop of a pair of flip flops, along with the question (in Portuguese) 'What colour do you see?'
As we saw with the dress, the colours in the photo have been distorted. The amount of light in the background means our brains can't actually determine what colour the flip flops are - gold and white, blue and black, or even grey and blue.
que cor vocês tão vendo? pic.twitter.com/IBk6upSZz7— arthur (@positivedemi) November 17, 2016
People are already debating it on Twitter. Of course.
I see white and gold flip flops... what do you see? pic.twitter.com/I35iYnlNLp— Sam (@SamGolbach) November 20, 2016
Others are convinced they are black and blue.
it's black and blue shut up whoever says white and gold get your eyes checked smh https://t.co/rMRe92omXe— maya (@simplydjh) November 20, 2016
Some think blue and grey.
THE FLIP FLOPS ARE BLUE AND GREY— bre (@breannaisner) November 21, 2016
And most people just really don't want to go down this road again.
Right I thought the dress was blue and black but I think the flip flops are gold and white and now I'm questioning everything about life ��— Kevin (@thatspeckyguy) November 21, 2016
Go to sleep Jane. At least stop worrying over what colour the flip flops are (blue and grey).— Jane Hamill (@janeybainy) November 21, 2016
For the record, the manufacturers Havianas have confirmed that the flip flops are actually dark blue and blue.
But, what colour do you see?