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.
While many people concluded that all four cups would receive the coffee at the same time, user @Purp encouraged them to "look closely".
Her followers continued to guess which cup would receive the coffee and she kept telling them to pay attention because the answer was "right there".
The correct answer? Cup five. Why? Because all the funnels leading to the other mugs are blocked.
Once the poster had pointed that out to her followers, they were amazed how long it took them to notice that detail.