Optical illusions fool us by violating our assumptions about what we see. The end results of how our brains process visual cues can be fascinating at times. Here's a somewhat simple, but extremely effective illusion, that exemplifies just that. Processing objects based on their surroundings is the match that lights the fire for this illusion.
Small paper ovals, when placed in front of a moving paper background, will appear to change shape and undulate right in front of your eyes!
Here is a short video that shows the full effect:
Step 1: What You Need
You will need the following materials to make and present this illusion:
1) Several sheets of 8.5" x 11" printer paper
3) Masking tape or transparent tape
4) 1 clear, tabbed sheet protector
5) A drawing software program on your computer that has a gradient tool. I used Photoshop CS3, so I will give clear-cut instructions based on that software.
6) A printer