Dots and Lines
Stare at the pattern for 10 seconds or longer and then switch your gaze immediately to a white surface such as a blank wall or a piece of paper. What do you see?
Answer: you will see the exact opposite of the diagram: white squares on a black background.
Are the horizontal lines parallel to each other or are they sloped or curved?
Answer: They are parallel but put a ruler up to your screen to confirm this.
How many black dots can you count?