Being sharp-eyed and detail-oriented has its advantages. It makes you an expert at I Spy, and you’re frequently the first person to see the beach on a road trip. When you watch crime series, you may notice nuances that help you solve the mystery before the detective.

Most importantly, you’re quick to locate misplaced keys, TV remotes, and wallets. But can you spot the error in these photos? At first glance, this may appear to be a standard photograph of two trains, but did you notice the error? Here’s the solution:

The cars on the train are wrong. The one on the left only has passenger cars and no head cars. Meanwhile, the other one has two head cars and no cabooses at all. If you found that one easy, you can set a timer for the next one if you weren’t using one already.