Parallel vs cross-eyed viewing

There are two ways to fuse a stereogram: parallel viewing, where your eyes relax as if looking into the distance, and cross-eyed viewing, where your eyes turn inward as if looking at something close. Every puzzle on The Week Eye is made for parallel viewing.

Parallel viewing (wall-eyed)

Your eyes point slightly past the screen, almost parallel. The left eye sees the left repeat and the right eye sees the next repeat to the right. Images made for this method show the hidden picture floating in front of the background.

• Bring your face close to the screen so everything blurs.
• Keep looking "through" the screen and lean back slowly.
• Stop when the two dots above the image become three, and hold that.

Cross-eyed viewing

Your eyes converge in front of the screen. The left eye now sees the repeat to the right and the right eye the repeat to the left. On an image made for parallel viewing, this reverses the depth: the hidden word or shape appears sunk into the pattern. It is still readable, and some people find cross-eyed viewing easier at first.

• Hold a finger halfway between your eyes and the screen and look at its tip.
• The image behind it doubles. Move the finger until the two dots above the image become three.
• Remove the finger without moving your eyes and let the image come into focus.

How to tell which one you are doing

Look at the depth. If the hidden shape floats toward you, you are viewing in parallel. If it looks carved into the background, you are crossing your eyes. Either way, you can type the answer you see.

Which is better

Parallel viewing is more relaxing and is what the puzzles are tuned for. Large monitors make it harder, because the repeat stays near eye width and your eyes must diverge more at a distance; sit close to a large screen. Cross-eyed viewing works at any distance but tires the eyes faster. Try both on the practice lessons and keep what works.