Hidden-Message Optical Illusion: How to Read the Stretched Text

This tangle of black lines hides a holiday greeting. Hold the image at a very low angle and two lines of text appear: "We wish you a Merry Christmas" when you look along it one way, and "And a Happy New Year" when you turn it a quarter turn and look along the other side. If you cannot see it straight on, that is normal. The letters are stretched so far that they only regain their shape when your viewing angle squashes them back.

A Hidden-Message Optical Illusion Viewed at an Angle

The puzzle as it circulated online in December 2015, shared by the Twitter account Fascinating Pictures. Both messages are drawn into the same grid of lines.

How to read the hidden message

The trick works on a phone, a tablet or a laptop screen, and it is easier than it first looks.

Make the image as large as you can. On a phone, open it full screen.
Tilt the device away from you until you are looking across the screen almost edge-on, as if sighting along a ruler. Bringing the bottom edge, near the charging port, up toward your eye works well.
Close one eye. With both eyes open, your brain tries to merge two slightly different views, which blurs the faint letter shapes. One eye gives a single, flatter picture.
Rotate a quarter turn and repeat. The vertical strokes hold the first line of text; the horizontal strokes hold the second.

On a computer you can get the same effect without moving your head: shrink the picture in one direction only, for example by squeezing its height in an image editor. The first message jumps out at about one eighth of the original height.

Why your eyes cannot read it head-on

Each letter has been stretched to many times its normal length in one direction. Seen from the front, a capital E becomes a few long bars with short stubs between them, and those bars merge with dozens of decoy lines that run the full width of the picture. Nothing looks like a letter, so your visual system gives up looking for words.

When you tilt the screen, perspective does the reverse of the stretch. Distances that run away from your eye are compressed, while distances across your view stay almost the same. The long bars shrink back into compact strokes, and the letters return to normal proportions. The decoy lines that run in the other direction are thinned down into a faint haze, so the words stand out.

Your brain is also very forgiving with imperfect type. Experienced readers fill in missing or smudged parts of letters without effort, especially in a familiar phrase, so a rough, streaky "MERRY CHRISTMAS" is easy to read once the proportions are close enough.

An old trick called anamorphosis

Pictures that only make sense from a particular angle have a long history. Artists call the technique anamorphosis, from the Greek ana- ("back" or "again") and morphe ("shape"). The earliest known example is a stretched drawing of an eye by Leonardo da Vinci in his Codex Atlanticus, and later Renaissance painters used the effect to hide jokes and messages.

The most famous example is Hans Holbein the Younger's 1533 painting The Ambassadors in London's National Gallery. A strange diagonal smear across the floor turns into a human skull when the viewer stands close to the right-hand side of the canvas and looks back along it. It is a reminder of death hidden in a portrait of two wealthy, confident young men, the French diplomat Jean de Dinteville and the bishop Georges de Selve. One theory holds that the painting was meant to hang beside a staircase, so that people walking past would suddenly catch the skull.

The same principle shows up in everyday life. Words painted on roads, such as "BUS LANE" or warnings about children crossing, are deliberately drawn very long and narrow so that drivers, who see the road at a shallow angle, read them with normal proportions. Pavement artists such as Kurt Wenner and Julian Beever use the same geometry to make flat chalk drawings look like holes or cliffs from one chosen viewpoint.

What the puzzle does and does not test

Posts like this often suggest that only a clever or sharp-eyed few can solve them. That is not what is going on. How quickly you see the text depends mostly on screen size, brightness, how far you tilt, and whether you have seen this type of puzzle before. It is not a test of intelligence or eyesight.

A few practical points help if you are struggling:

Small screens make the effect harder, because the decoy lines become very dense. Zoom in.
Glare and reflections can wash out the thin strokes, so turn up brightness and avoid bright light behind you.
If you wear glasses for reading, keep them on. You are still focusing on a nearby screen.
Do not tilt too far. At a completely flat angle everything disappears; the sweet spot is just above that.

If you have trouble reading normal text, or notice changes in your vision, that is a question for an eye doctor, not for an internet puzzle.

Make your own hidden-message picture

You can create a simple version in a few minutes. Type a short word in bold capital letters, then stretch it to about eight or ten times its height while keeping the width the same. Add long, straight lines that cross the whole picture in both directions so the letters blend in. To hide a second message, rotate it 90 degrees, stretch it the same way, and layer it over the first.

Show the result to a friend and let them discover the tilt for themselves. Half the fun of this kind of puzzle is the moment the noise suddenly turns into words.

Sources: Fascinating Pictures (Twitter) · Wikipedia: Anamorphosis · Wikipedia: The Ambassadors (Holbein)

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