If you're a fan of brain teasers, you're going to love this! This puzzle surfaced on Reddit last April and has been driving Internet users crazy since it was posted. It was made in Japan and can apparently tell you how much your brain has aged so far. So get ready–breathe out, and try to focus because it is not easy!Can you spot the butterfly, duck and bat? CaptureA butterfly, a duck, and a batThe image looks like it's straight out of an old-school children's book and shows a father doing work around the garden with his kids. But there are actually three animals hidden in the drawing: a butterfly, a duck, and a bat.If you can only spot one of them, you might be suffering from some form of dementia–like Alzheimer's disease–and your brain is in pretty bad condition.If you're able to spot at least two of them, you should be good: your brain is fine; everything's in order.If you spotted all three of the animals hidden in the drawing, congratulations! Your brain is youthful and fresh. If you're an adult, please write to us and tell us your secret!And don't worry if you didn't do so great! This test actually has zero medical value, obviously. Maybe you just need a nap... Also, it's not an easy test to pass, in fact, and even at Gentside, we had a hard time figuring it out!We bet you can't wait to share this test with your friends. Enjoy!Check out the video above to see where the 3 animals are hidden!