People are having the hardest time trying to figure out if the mug in this video is round or square.
Tony Fisher has created a mug that is seemingly both square, round and horrendously confusing all at the same time, which has obviously sparked furious debate online as to the bizarre nature of this thing.
You can clearly see the mug is circular in the foreground, but just behind it, there's a mirror which shows the mug as being square.
Tony fills the mug with milk and stirs it around with a spoon, all the while you see in the mirror the square shape, which seemingly confirms there are no camera tricks at play.
Either the mirror or indeed the mug is a magical one or, more likely it's just a clever trick of the eye thanks to the shape of the mug and the positioning we're being shown.
If mind-bending mugs are you cup of tea, this one surely offers a strong brew. But this isn't the first nor surely the last time a debate like this will come around.
The progenitor of this 'round or square' and 'Laurel/Yanny'-esque debates was arguably a particular maddening dress we were all introduced to on February 26 2015.
The dress captivated the globe and even had people like Kim Kardashian and Taylor Swift weigh in to try and crack the mystery.
What color is that dress? I see white & gold. Kanye sees black & blue, who is color blind?
— Kim Kardashian West (@Kim Kardashian West)
Next was the great 'Laurel or Yanny' debate, which heard a recording from 2007 by actor Jay Aubrey Jones for the website Vocabulary.com
Jones apparently recorded 36,000 words for the website and when saying the word 'Laurel' a student heard 'Yanny', and the whole thing went viral.
The student then posted the clip online and asked people to say what they heard - Laurel or Yanny.