What Is The Coffee-Pouring Puzzle? Viral Brain Teaser Sparks Debate

If you want to solve the latest viral internet head-scratcher, you'd better have some coffee first.

Twitter user @Purp originally shared a coffee-lover's brainteaser on Thursday afternoon and it quickly got nearly 2,000 comments and another 2,000 retweets.

The game involves a photograph which shows a hand pouring coffee down a series of pipes, which lead into four different cups. Players are asked to guess which of of the four labeled cups would fill first.

Guesses from Twitter users widely varied:

The correct answer? Cup number 5 — but only because you probably weren't paying close enough attention. If you take a close look at the puzzle, you'll notice that the pipes leading to cup numbers 4, 9, and 7 are completely sealed off, so it would be impossible for any liquid to drip into them. Some Twitter users were quick to get the answer, and one person even illustrated exactly why cup number 5 is the only possible answer.

The coffee brainteaser is just the latest logic puzzle to sweep the web. Others include TED-Ed's green-eyed game, deemed the "world's hardest logic puzzle." It involves 100 green-eyed logicians imprisoned on an island who can escape, but only if they know they have green eyes...which they don't.

Here's the answer:

Another puzzle, involving various fruits, also gained traction on Facebook. The teaser involves seemingly simple math problems, with apples, bananas, coconuts, and apples in the equations. Answers to three of the equations are given, but the player must guess the answer to the fourth equation, which is very very easy (again, but only if you're paying attention).

Answers in the comment sections varied. But there's only one correct guess: 14 (hint: size matters).