1. This is the familiar Necker cube. Do you see what you are looking at?
If you look steadily at it, the figure will flip-flop; the front surface becomes the back surface and vice versa. The changes are spontaneous and out of your conscious control. Try as you will, you cannot keep the box in one orientation.
2. Pattern sets and camouflage
In (A) the boxes and circles are instantly organized
by the visual system into horizontal patterns.
3. Shape constancy
4. The remarkable brain doesn't need complete images to get vision. It fills in the blanks from memory and experience. What do you see below?
5. By injecting perspective in drawings, such as converging lines and different sized objects, the illusion of a real scene is evoked. By altering the normal perspectives, false illusions are created. What do you see below?
Actually, the apparent white 'Overlay' figure is not really there.
6. What's wrong with the normal caricature below?
If you examine it closely, you will realize that both eyes are on the same side of the nose.
7. Which pennant is larger?
The answer is the same.