Is your brain awake and energized? If not, you may want to grab a cup of coffee to figure out this head-scratching puzzle.

According to IFL Science, the brainteaser was shared by Twitter user @_herbeautyxo and has been stumping web users ever since. The image shows coffee being poured into a network of pipes and boxes. It seems there are four places the liquid could end up and each is represented by a numbered cup. Based on the shape and arrangement of the pathways, you have to guess which vessel will catch the coffee first.

Plenty of users had guesses, but few of them answered correctly. But once you know what to look for, the puzzle becomes deceptively simple (scroll down if you want to find out the answer). 

Three of the four pipes are blocked off, so the only possible spot for the coffee to exit from is the remaining pipe above cup five.

Your brain doesn’t always interpret what you see in front of you accurately, even when it’s given a caffeine boost. If you need more evidence, check out these award-winning optical illusions and brain puzzles.

[h/t IFL Science]