# Strangest optical illusions you have seen **URL:** \ **Category:** In My Humble Opinion\ **Created:** [June 24, 2004, 12:04am UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907 "2004-06-24T00:04:54Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![SamIAm336](https://avatars.discourse-cdn.com/v4/letter/s/4491bb/32.png) [@SamIAm336](https://boards.straightdope.com/u/SamIAm336)\ **Post date:** [June 26, 2004, 3:22pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/21 "2004-06-26T15:22:51Z")
I saw bands of darkness shining like light near sunset a few times driving home from work. Then I did a little research and found out about Anti-crepuscular rays. It is the weirdest thing I have ever seen. [http://www.sundog.clara.co.uk/atoptics/antray3.htm](http://www.sundog.clara.co.uk/atoptics/antray3.htm) ---
**Author:** ![Brynda](https://avatars.discourse-cdn.com/v4/letter/b/e79b87/32.png) [@Brynda](https://boards.straightdope.com/u/Brynda)\ **Post date:** [June 26, 2004, 6:39pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/22 "2004-06-26T18:39:30Z")
No anecdotes, just wanted to thank **SamIAm336** for the cool link. ---
**Author:** ![Greywolf73](https://avatars.discourse-cdn.com/v4/letter/g/d9b06d/32.png) [@Greywolf73](https://boards.straightdope.com/u/Greywolf73)\ **Post date:** [June 26, 2004, 10:42pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/23 "2004-06-26T22:42:12Z")
I was driving home once late at night and came upon a slight rise in the road. A few yards ahead of me, I could see flashing red lights that didn’t seem to be moving. The lights seemed to be higher than a car and my mind helpfully filled in the blanks for me and I became convinced there was a semi truck stopped in the middle of the highway and I was fast approaching the back end. I slammed on my brakes to find myself stopped in front of a blinking red traffic light. I have no idea where I got the idea that there were two blinking red lights instead of just one. Guess I was more tired than I thought. When I was a kid, some friends and I ventured out into our church graveyard one night, trying to scare each other silly by pointing out “ghosts” to each other. Well, lo and behold we actually did come across a real “ghost”–the small figure of a woman who seemed to be dancing on top of a grave on the other side of the graveyard. The more we stared at “her” the more she looked like a tiny little woman dancing. We could even see her dress blowing in the wind! Finally, one of us got brave enough to go closer and investigate. The ghostly woman turned out to be a combination of flower arrangment and ribbons blowing in the wind at just the right angle. ---
**Author:** ![KRC](https://avatars.discourse-cdn.com/v4/letter/k/45deac/32.png) [@KRC](https://boards.straightdope.com/u/KRC)\ **Post date:** [June 27, 2004, 1:33am UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/24 "2004-06-27T01:33:06Z")
In 1991 I looked out a bus window and was quite alarmed to see a black triangle in the sky over southeastern Albuquerque. After staring at it a few seconds, however, I realized it was an airplane. It was heading for the airport and it’s tilt as it landed caused it to look like a triangle; because it was between me and the sun it looked black. The fact that the bus window was dirty contributed to the illusion. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 27, 2004, 2:01am UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/25 "2004-06-27T02:01:00Z")
> [@Rick](#): > > I crested a hill, and the road looked like a nice gentle downgrade. But for some silly reason I had to keep pedaling. The last time it happened, the culprit turned out to be a strong headwind. :smack: I’m sure it because a river flowed effortlessly beside the road in the same direction. The strangest optical illusion I’ve seen was a wheel appearing to turn backwards, in broad daylight, in real life (not TV). I was looking out through a bus window which, for some reason, had plastic film with a wavy pattern. It provided the necessary stroboscopic effect. It only lasted a fraction of a second though. Also I remember sitting in a train and seeing an airliner in the distance, floating above a mountain and not moving at all. It was caused by the motion of the train - the train and airliner were moving in the opposite directions, and the mountain was between the train and the airliner. ---
**Author:** ![nocturnal\_tick](https://avatars.discourse-cdn.com/v4/letter/n/3d9bf3/32.png) [@nocturnal\_tick](https://boards.straightdope.com/u/nocturnal_tick)\ **Post date:** [June 27, 2004, 8:20am UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/26 "2004-06-27T08:20:05Z")
I have also seen car wheel apparently moving backwards whenever I go through a this particular tunnel when visiting friends. (It’s on the M25) The lights must provide the right strobe effect. Also when I used to travel by train to see those same friends, it really disturbed me when I got on the next train at Cambridge station, where the platforms are parallel and an adjacent train starts to move you think you are moving yourself but into the station rather than out. Only freaks me for a fraction of a second but freaks me nonetheless. ---
**Author:** ![picunurse](https://avatars.discourse-cdn.com/v4/letter/p/7bcc69/32.png) [@picunurse](https://boards.straightdope.com/u/picunurse)\ **Post date:** [June 27, 2004, 11:29am UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/27 "2004-06-27T11:29:27Z")
I used to drive across Lake Washington to Redmond WA (we are Microsoft; resistance is futile) The drive to work was uneventful, but any day it was sunny, as I passed the Microsoft campus, Mount Rainier would suddenly appear to be right over the hill (its about 80 miles away.) It would loom large for about 1/2 mile. the road dipped a bit, the back up to what appeared to be the same level. But, the Mountian was GONE! I couldn’t see it again until I got to the bridge, but it looked 80 miles away as it should. There’s another place along the same highway where the Olympic mountains are suddenly huge for a short distance then settle back into their normal position. (Please, some other Seattlite confirm this so these folks don’t think I’ve gone 'round the bend.) ---
**Author:** ![SnakeSpirit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snakespirit/32/7271_2.png) [@SnakeSpirit](https://boards.straightdope.com/u/SnakeSpirit)\ **Post date:** [June 29, 2004, 7:38pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/28 "2004-06-29T19:38:38Z")
I have two stories, but I’ll do them in two different posts: 1. ``` I had recently arrived in VietNam and was assigned to the 4th Division. We were going through a week of "VietNam Orientation" and were crammed in a barracks with bunk beds 3 high and 2 feet apart. All our belongings hung off the end of the bed in duffle bags. ``` In the middle of the night I woke up and there, in the shadows at the foot of my bed was a V.C. He was wearing the wide conical hats that Vietnamese wore, dressed in black pajamas, and he looked like he had just seen me wake up, as he seemed to be frozen in mid-lunge, his bony hands curled like claws ready to grab my throat! I launched myself up from the bed and leapt at the threatening figure, my hands reached for his throat and I shouted a growl as I leapt in order to wake my companions so I could have help dealing with this invasive threat. So tempting to use a spoiler… My hands closed on empty air as they passed through the shadows underneath the curl of a blanket on the top bunk, a curve of blanket that made the illusion of a conical hat. My body brushed past duffle bags whose shadows simulated a black clothed figure crouching at the foot of the bed. I fell to the floor, mortified. The fire watch flipped on the lights and I had some embarrased explaining to do. 蛇 ---
**Author:** ![SnakeSpirit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snakespirit/32/7271_2.png) [@SnakeSpirit](https://boards.straightdope.com/u/SnakeSpirit)\ **Post date:** [June 29, 2004, 7:39pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/29 "2004-06-29T19:39:43Z")
I have two stories, but I’ll do them in two different posts: 1. ``` I had recently arrived in VietNam and was assigned to the 4th Division. We were going through a week of "VietNam Orientation" and were crammed in a barracks with bunk beds 3 high and 2 feet apart. All our belongings hung off the end of the bed in duffle bags. ``` In the middle of the night I woke up and there, in the shadows at the foot of my bed was a V.C. He was wearing the wide conical hats that Vietnamese wore, dressed in black pajamas, and he looked like he had just seen me wake up, as he seemed to be frozen in mid-lunge, his bony hands curled like claws ready to grab my throat! I launched myself up from the bed and leapt at the threatening figure, my hands reached for his throat and I shouted a growl as I leapt in order to wake my companions so I could have help dealing with this invasive threat. So tempting to use a spoiler… My hands closed on empty air as they passed through the shadows underneath the curl of a blanket on the top bunk, a curve of blanket that made the illusion of a conical hat. My body brushed past duffle bags whose shadows simulated a black clothed figure crouching at the foot of the bed. I fell to the floor, mortified. The fire watch flipped on the lights and I had some embarrased explaining to do. ---
**Author:** ![SnakeSpirit](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snakespirit/32/7271_2.png) [@SnakeSpirit](https://boards.straightdope.com/u/SnakeSpirit)\ **Post date:** [June 29, 2004, 8:14pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/30 "2004-06-29T20:14:51Z")
Oops, sorry, not sure how that happened. 1. ``` I had been in VietNam about six months or so, mostly out in the boonies, but it was monsoon season, raining all the time, and we had pulled back to Pleiku, Camp Enari, to wait out the rains. ``` Everyone had to do their share with guard duty, and one drizzly night it was my turn. I got awakened for second or third watch. It was dark out. You could hardly see the concertina wire 30 feet out, though there was enough light to see my immediate area. Suddenly I saw what appeared to be to top of someone’s head bobbing along the sandbag wall forming the side of the bunker. Dark hair, cut short in a crewcut. I imagined an NVA infiltrator sneaking along the wall, ready to toss a hand grenade in through the front opening… I pulled back the slide on my M-16, locked and loaded a round, drew a bead on the top of the head and yelled, “HALT!” Then, through my sights, I saw a black rat peeping up at me with his beady eyes and twitching nose and bristly black fur. I let him live. ---
**Author:** ![TellMeI\_mNotCrazy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tellmei_mnotcrazy/32/3419_2.png) [@TellMeI\_mNotCrazy](https://boards.straightdope.com/u/TellMeI_mNotCrazy)\ **Post date:** [June 29, 2004, 8:27pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/31 "2004-06-29T20:27:21Z")
I’ve seen the Chrysler Building disappear. April or so, it was rainy/foggy/misty, whatever, and I was walking towards Grand Central Station, with the Chrysler Building positioned beyond it. Now, I take this walk every day, so I know the stupid thing is there, but it’s one of my favorite buildings so I always look up at it. The fog and lighting made it truly look as if the Chrysler Building had simply ceased to exist. It wasn’t “hard to see” or “barely discernible”, it was _gone_. Buildings to the left and right were still fairly visible. Chrysler Building? Gone. It was fascinating - even though I knew why I couldn’t see it, I couldn’t stop gaping at it. ---
**Author:** ![TellMeI\_mNotCrazy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tellmei_mnotcrazy/32/3419_2.png) [@TellMeI\_mNotCrazy](https://boards.straightdope.com/u/TellMeI_mNotCrazy)\ **Post date:** [June 29, 2004, 8:32pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/32 "2004-06-29T20:32:38Z")
Oh, one other one. Flying from Johannesburg to Amsterdam… Looking out of the window, with this amazing view. At one point, the way the breaks in the clouds were arranged, and the way the light hit them, the clouds looked astonishingly like mountains. I was captivated. Then, doing some quick mental calculating, I looked up at the flight map. We were flying over the Alps. :smack: I always thing of that when I hear the song 3 x 5: _And strange how clouds that look like mountains in the sky are next to mountains anyway – John Mayer_ ---
**Author:** ![DaToad](https://avatars.discourse-cdn.com/v4/letter/d/67e7ee/32.png) [@DaToad](https://boards.straightdope.com/u/DaToad)\ **Post date:** [June 29, 2004, 10:19pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/33 "2004-06-29T22:19:33Z")
I was driving through West Texas early one night watching some very strange lights off in the distance. I had no idea what it was, but hey, it was Texas after all and I thought maybe maybe it was a lightning from a sudden thunderstorm or something. Only later did I find out I had seen the Marfa Lights. ---
**Author:** ![NardoPolo](https://avatars.discourse-cdn.com/v4/letter/n/ecae2f/32.png) [@NardoPolo](https://boards.straightdope.com/u/NardoPolo)\ **Post date:** [June 29, 2004, 10:22pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/34 "2004-06-29T22:22:54Z")
If you follow a metallic tanker truck (like a truck carrying milk or gas or something), you can look at the reflection on the back. If it’s like most of the trucks around here you will see the reflection of the painted lines in the road to your right and your left, and a reflection of the road underneath you stretched out to infinity. The effect is that you are looking at a reflection that seems to include everything except you. This still gives me the heebie-geebies. ---
**Author:** ![Rex\_Fenestrarum](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rex_fenestrarum/32/7265_2.png) [@Rex\_Fenestrarum](https://boards.straightdope.com/u/Rex_Fenestrarum)\ **Post date:** [June 29, 2004, 11:44pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/35 "2004-06-29T23:44:21Z")
> [@Rick](#): > > The second time was a bike tour I took a few years back. I crested a hill, and the road looked like a nice gentle downgrade. But for some silly reason I had to keep pedaling. Ahhhh… Similar to [Booger Hill](http://www.roadsideamerica.com/tips/getAttraction.php3?tip_AttractionNo==1796) in Georgia. Local legend has it that two black guys were lynched on this spot for raping a white woman and now their “ghosts” will push cars up a hill. Aside from the fact that I can’t figure out why ghosts of two lynched black guys would want to spend eternity pushing cars full of giggly white teenagers around, it’s just a neat optical illusion - even if it was shown on _That’s Incredible_ back in the day. ---
**Author:** ![kittenblue](https://avatars.discourse-cdn.com/v4/letter/k/ba8739/32.png) [@kittenblue](https://boards.straightdope.com/u/kittenblue)\ **Post date:** [June 30, 2004, 12:59pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/36 "2004-06-30T12:59:07Z")
When I lived at Ft. Benning, Ga. there was a huge old outdoor swimming pool called Russ Pond that had been allowed to revert to nature. There were still markings around the tile edge giving the depth, and tile steps that would lead down into the water, but the whole thing was a giant duck pond filled with plants and turtles and fish. One day, they decided to drain the pond. I’m not sure why. But we stopped by, not knowing this had happened, and all that was left was a huge expanse of mud with a tiny stream running through the middle. After years of seeing that vast surface of water, to see the bottom was very disconcerting, and I could not get my eyes to focus on the bottom. It was much, much deeper than the faded depth markings had indicated, but my brain could not process the distance at all. The whole time we were there that day I could not get my eyes to focus on the bottom…trying made me dizzy. It was as if my brain was trying to focus on where it thought the bottom should have been, not where it actually was, and kept switching back and forth between surface, imagined depth and actual bottom. ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [June 30, 2004, 1:33pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/37 "2004-06-30T13:33:46Z")
The one I always found weird and inexplicable is the effect whereby mountains always cast triangle-shaped shadows, no matter what shape the mountain is. An example: [http://www.sundog.clara.co.uk/atoptics/mshadim1.htm](http://www.sundog.clara.co.uk/atoptics/mshadim1.htm) ---
**Author:** ![MC\_E](https://avatars.discourse-cdn.com/v4/letter/m/c77e96/32.png) [@MC\_E](https://boards.straightdope.com/u/MC_E)\ **Post date:** [June 30, 2004, 3:05pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/38 "2004-06-30T15:05:12Z")
A friend of mine that works as a conductor for the railroad told me about one of the most dangerous optical illusions. If you are standing between two trains and they are both moving, you become very disoriented, very quickly. About the only thing you can do is drop to the ground and wait for one of them to stop or pass. ---
**Author:** ![Finagle](https://avatars.discourse-cdn.com/v4/letter/f/b19c9b/32.png) [@Finagle](https://boards.straightdope.com/u/Finagle)\ **Post date:** [June 30, 2004, 3:35pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/39 "2004-06-30T15:35:24Z")
Near where I live, Rte. 1A does one of those “mystery hill” things. To my eye, it looks like the road is sloped upwards. But to my bicycling legs, it’s clear that there’s a slight downward slope. For a while there, I was feeling all proud of myself, getting that extra burst of energy on an uphill run. One of these days, I’ll have to bring a level with me and figure out what’s going on there. ---
**Author:** ![brix11](https://avatars.discourse-cdn.com/v4/letter/b/c37758/32.png) [@brix11](https://boards.straightdope.com/u/brix11)\ **Post date:** [July 15, 2004, 2:06pm UTC](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907/40 "2004-07-15T14:06:54Z")
One of my mom’s bedroom windows looked out on to our yellow and white striped, above-ground swimming pool. Every now and then we could see what can only be described as a reflection of this pool on her bedroom ceiling. Although somewhat blurry, we could clearly make out the shapes and colors of the pool and water. As a kid it used to freak me out, but I wish now that I had tried to photograph it and make note of the sun’s position and all that. [Previous page](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907.md?page=1) [Next page](https://boards.straightdope.com/t/strangest-optical-illusions-you-have-seen/251907.md?page=3)