Algodoo

Look at the two lines. Which line segment is longer, the red one or the blue one?

The answer is: they are the same length. Although the blue line segment appears longer, this is actually because the position of the blue line is misleading—it happens to be placed at the halfway point of the red line segment. This creates the impression that 'the blue line segment is much longer than half of the red line,' which leads to the illusion that 'the blue line segment is longer than the red line.'