Susana and Lucas are rowing in the river, but something seems to be wrong. The water comes to life and three faces appear. You know where they are? IQ, short for intelligence quotient, is a measure of a person’s reasoning ability!

Many colleges and universities also use exams similar to IQ tests to select students. Think that you’re observant enough to spot the subtle differences between pictures? Get your eyes ready because this is tricky.

If you haven’t found the answer yet, don’t worry; we have it here. Others found the inaccuracy difficult to see, and I was one of the few who missed the tiy detail. When you see it, however, you’ll know immediately away that something isn’t quite right!