This document contains several optical illusions and visual puzzles designed to trick the eye and challenge first impressions. It includes images that appear warped, curved, or distorted but are actually straight or parallel lines. It also contains images that appear animated but are static, and shapes that appear concave or convex depending on how they are viewed. The document aims to demonstrate how visual perception can be fallible and influenced by context, prior experiences, and assumptions.

1. Optical Illusions II

3. Can you unweave this web and find the hidden word within it?

4. ANSWER: A little color-coding helps to reveal the truth.

5. Stare at the red dot long enough, and the grey stripes will disappear.

6. Believe it or not, these lines are straight and parallel.

7. Another "false spiral" -- actually a series of concentric circles, hard as it may be
to believe. To prove that there's no spiral, try tracing your finger around one of
the circles. You'll see that it never moves inward or outward.

8. What's your first impression of this image? Yellow arrows pointing left, or green arrows
pointing right? There is no "correct" answer, but different people perceive this image
differently at first.

9. Try moving your mouse pointer down across this image, following the pointer closely
with your eyes. You should see a rippling effect moving through the picture -- even
though it's a completely static image!

10. Believe it or not, this image is not animated. The effect persists only in
your peripheral vision; if you focus on any one of the spirals, it will stop
moving.

11. This three-in-one illusion includes a false spiral, an impossible Escher-
esque structure, and what appears to be a seriously warped floor...

12. With the black and white squares removed
from the tiles, we see that the lines on the
floor are perfectly straight.

13. Can you tell where on this curve the lines are the longest, and where they are
the shortest?

14. ANSWER: They are all the same length.

15. Are the walls of this house facing outward, or inward?

16. ANSWER: Depends on how you look at it. If you isolate the top portion of
the image, the house appears to be concave, facing inward. Isolate the
bottom, and the perspective is reversed.

17. Which of these two dots is in the true center of the circle?

18. ANSWER: With the distracting lines out of the
way, it's apparent that the green dot is at the
center.

19. Which square is a lighter shade, A or B?

20. ANSWER: Taken out of context, you can see A
and B are the same shade. Our familiarity
with light and shadow tricks us into thinking B
is "actually" lighter than A.

21. Here's a simple one. Are these two rows of squares perfectly parallel?

22. ANSWER: They are indeed perfectly
parallel, which becomes more apparent when
the line between them is highlighted.