Look at those two straight lines with arrows. Guess which is longer?

Is it the one above?

No! In fact, they are the same length.

This is the famous Miller illusion, also known as the arrow illusion.

It means that if you add two diagonal lines at both ends of a straight line and two diagonal lines at both ends of another straight line, then two straight lines with the same length will appear much longer than the latter.

I recommend it carefully.