Which of these three horizontal lines is the longest?
You probably said the middle one, but it’s a trick question: they’re all the same length. The arrows added to the ends affect your perception of the overall line length even though I’m asking you about exact measurements.
If I asked you to mark the midpoint of the third line, the one that looks like an arrow, you’d probably end up putting it right of center despite already being aware of the optical illusion. The arrowhead on the left overshadows that section of the line, and makes it appear shorter because the eye responds to the open end of the arrowhead as an implied line, so you end up registering it as somewhat separate from the portion of the line that doesn’t have anything overlapping it. Additionally, the arrow that serves as the tail on the right side widens the overall shape and draws the eye in that direction even though it’s not the section I’m asking you to consider.
Think this is bad? Wait until you hit more complex forms like the human body.
[Warning: this explanation is very image-heavy.]
imagine corgis as non-domesticated animals. living out in the wild. traveling in packs