A baffling puzzle posted on Twitter has left the web stumped, as viewers struggle to determine the correct answer.
The brainteaser, which was shared on by Twitter user @Purp, shows a pot of coffee being poured into a sketch of different pipes, which collectively lead to four coffee mugs.
The puzzle asks users to figure out which of the coffee mugs the liquid will reach first - and it's harder than it first appears, according to the Daily Mail.
The user who uploaded it told her followers: "Let's see whose brain is working". It was quickly shared thousands of times as users argued over the right answer.