Not a flying carpet

This photo was called an "accidental optical illusion" when it was posted at Reddit.  I think that's a very apt description.  Apart from the flag shadow paralleling the board, there's also the flagpole shadow oriented reasonably well re the microphone boom.  Very cool illusion.

Reposted from 2011 to accompany the next post.

These cubes are NOT MOVING

An incredible optical illlusion.  I tried covering up the arrow prompts with paper, but the cubes still "move".

Sadly I've never understood how to embed a gif, so I have to settle for embedding a YouTube video of this gif.  Gif at Cliff Pickover's X page, via Nag on the Lake.  The resolution (and duration) are better at the original.

If you enjoyed this, spend an hour or two browsing my other 89 optical illusion posts.

The "changing room" illusion

"Intertwining" illusion

What you are looking at is four concentric circles of boxes.  Credit to Baingio Pinna.

Optical illusions for those in a hurry

Forty of them in eight minutes (many of which I've previously covered in TYWKIWDBI in the optical illusions subcategory).  Via Neatorama.

Sound visualized

Also works nicely in the optical illusions category of the blog, since none of the dots actually move continuously (they just wiggle back and forth).

Looks like phocomelia ("T. rex arms")...

... but it's just an optical illusion.  The mother has normal arms.  Look closely.

Phocomelia.

Via.  Reposted from 2018 because I encountered it again while searching for something else and was fooled again.

Yet another optical illusion

For this illusion to be effective, you need to view a gif, and since I've never learned how to embed gifs, I'll just link it here.  After 22 seconds, the static image above changes for 2 seconds to this black-and-white one -

- which your brain will see in full color (reversed from the top embed). 

The effect is probably similar to the Troxler's fading that I blogged back in 2011.

I thought I had blogged this one before, but I couldn't find it in my archive of optical illusions (84 to date, but some are undergoing linkrot over the years, so don't delay forever in browsing them).

The middle strip is NOT a gradient

I checked it myself by selecting a segment from the left of the strip and pasting it on to the right side of the strip.  It disappeared.  Found in the opticalillusions subreddit.

These four balls are congruent in terms of color

All four are the same color (not the same color throughout their area, but congruent in terms of color at each point).  Via the opticalillusions subreddit, where readers have confirmed the identical colors using digital sampling techniques.

Optical illusion best viewed from a distance

Hard to see close-up, but from a distance [or by "zooming out" on your screen] the dark spaces between the rocks spell "The stones will cry out" (a Biblical phrase).  I don't know the original source for this somewhat-viral image.

There is no yellow circle in this image

It's an optical illusion resulting from normal subtractive color mixing.  I double-checked by opening the image in a separate tab, then enlarged the image to the max and took a screencap of the center of the "yellow":

Via Neatorama, where you can access some discussion and source information.

Platform 9 3/4 optical illusion

Other examples of the Best Illusions of 2023 are embedded at Kottke, along with a link to all the competition winners. 

Gate

Located in Vienna.

Can you see the hidden tiger in this image?

It might help to zoom.  Out. 

Via for the image (and the answer) is at Neatorama.

The truly remarkable "Ames window" illusion

I've posted the abbreviated version of this video; be sure to stick with it to the end to see the full effect.  A longer version of the video is here; it includes instructions on how to make the window at home.

There is NO RED COLOR in this image

It does look like there is a red letter and a red background on the other flag, but those are optical illusions - illustrated with closeups at Neatorama.

There is no solid color in this photo

The original black-and-white photo has been "colorized" with a criss-cross pattern of colored lines.  There are no solid color areas; your vision interpolates the rest of the color.  via Reddit.

False horizon resembles a "superior mirage"

The image above was reported and explained at The Guardian as a "superior mirage," defined as follows at Wikipedia:

"A superior mirage is one in which the mirage image appears to be located above the real object. A superior mirage occurs when the air below the line of sight is colder than the air above it. This unusual arrangement is called a temperature inversion, since warm air above cold air is the opposite of the normal temperature gradient of the atmosphere during the daytime. Passing through the temperature inversion, the light rays are bent down, and so the image appears above the true object, hence the name superior. "

A major tip of the blogging cap to reader Drabkikker, who points out in his comment that this is NOT an image of a superior mirage, but rather that of a false horizon.  The distinction between the two is carefully and lucidly explained in this video:

Those who would like to explore the physics of optical illusions and meteorology might enjoy making use of the engine displayed in the video, which is at this link.

The Coffer Illusion

Most people will interpret this image as perhaps a door panel; it may take a while to realize that there are actually 16 circles in this pattern.

Reposted from years ago to add an improved-quality image.