Which tracheal tube is longer?

When I first saw it, two questions immediately captured my attention: A) What is “tracheal tube”? and B) Will the illusion work for others, where I wasn’t even sure it worked for me. Still, based on its popularity on the various social networks (=read: Facebook), I suppose it is OK.

So, not being lazy, I have searched the web and learned that tracheal tube is a catheter (?!) that can be inserted into the patient’s trachea in order to establish and maintain clear airway…

Never would’ve guessed the day will come when we would have catheter illusions appearing on this site! It would probably be the last thing I could come up with, if someone asked me in prior to give my wildest prediction regarding future illusion submissions! In this illusion the lower tube should appear longer when positioned vertically… What do you think of it?

Few more examples of Gregor Wosik’s work:

You’ve probably recognized the pattern as one being often used in all kinds of optical illusion examples. From #Seemingly Bent category items, all the way to “Seemingly Moving Illusions” which are categorized inside the #Animations category. I still don’t truly understand what is so special with rectangles on grayish background, yet they aways do the trick! It must have something to do with all them subtle black and white shades each rectangle is equipped with, if you ask me…

Now let’s try and explain the science behind this: Troxler’s Fading or Troxler’s Effect is a phenomenon of visual perception you have just experienced moments ago. When one fixates a particular point, after about 20 seconds or so, a stimulus away from the fixation point (in peripheral vision) will fade away and disappear. The effect is enhanced if the stimulus is small, of low contrast, or blurred. It works best the further the stimulus is away from the fixation point.

Troxler’s fading was first discovered by Ignaz Paul Vital Troxler, back in 1804. It is part of the general principle in sensory systems that an unvarying stimulus soon disappears from our awareness. Here’s a fun experiment you can try yourself: place a small piece of paper on the inside of your forearm. You can feel it for a few seconds, but then the sensation is no longer present. This is because the tactile neurons have adapted. Now, if you jiggle your arm up and down, giving varying stimulation, you will continue to feel the paper until it falls off! Similar fading can be seen of a fixated stimulus when its retinal image is made stationary on the retina, a stabilized retinal image. One can induce an afterimage, usually by an intense, brief flash, such as when one is photographed using a photographic flash.

This causes an image to be bleached onto the retina by the strong adaptation of the rods and cones. In all these cases, the stimulus fades away after a short time and disappears. Troxler’s fading can occur without any extraordinary stabilization of the retinal image in peripheral vision because the neurons in the visual system beyond the rods and cones have large receptive fields. This means that the small, involuntary eye movements made when fixating something fail to move the stimulus onto a new cell’s receptive field, giving unvarying stimulation. One of the more famous examples we covered in the past was Lilac Chaser. Be sure to check Disappearing Effect category for many more examples of Troxler’s Effect!

If these kind of installations ring a bell, you’re right – artists like Guido Moretti and late Shigeo Fukuda experimented heavily with similar kind of ambiguous forms. If you haven’t already, be sure to check Underground Piano from Fukuda and Guido Moretti’s works of art. Let me show you how it works below:

Update: It appears the illusion works flawlessly in other languages to! First two appear to be Spanish and French versions, while I can’t seem to work out the last one on the right? Is it Klingon?

If you’re into scary illusions, there was this one particular picture that resembled today’s photo. I think the article went live almost 5 years ago under “Scary Illusion no.5” headline. Be sure to check it out and decide which one you like better. What I do know is that the real answer (for both of these pictures) is trickier than you think!

As for this first top ten list, I thought tattoos would make a great topic -after all, you have to really love an illusion to get one tattooed on you. This first tattoo is my personal favorite because it’s such a classic illusion subject -multiple meaning one. These work really well as arm  tattoos because you never know if someone will view it while your arm is raised or not, making it the ideal location for such a piece. This specific design was done by David Page. On the left, you have a queen, but when you flip her upside down, you have a king.

Next, the skull illusion tattoo involves one of my favorite types of illusions. What’s so great about skull illusions?  Let’s face it, they’re just so cool! It’s also a great idea for a tattoo since skulls are one of the most classic tattoo designs, but this interpretation brings the concept from cliche to chic.

Here’s another excellent skull illusion tattoo, this one involving two clowns holding hands while drinking. The tattoo, by Kate Hoogland, just might contain the most romantic skull illusion I have ever seen.

On the right, we have a brilliant rendition of M.C. Escher’s Drawing Hands illusion. The piece, done by Cheryl Volling, has some absolutely stunning shading, giving it the life-like appearance of the original Escher drawing.

This ambigram tattoo is great in that it incorporates some of the most important aspects of philosophy into an ambigram. It’s also particularly nice in that it is easy to read and doesn’t look strange from either direction, which is one of the hardest aspects in making an ambigram.

This saint/sinner ambigram is also easy to read, but rather than focusing on the arts and sciences, it focuses on religion. I think it really seems to denote the true duality of man.

Here’s another cool religious optical illusion, albeit in a a totally different style. If you don’t see the illusion, just back up a few more inches and then you’ll see that the image comes together to make the face and beard of Jesus.

On the right is another Escher tattoo, this one is on Flickr user’s alan.maia profile and features fish transforming into birds (and vice-versa) artwork. Maybe it’s just me, but I really love how worried that last fish in the tattoo looks.

We’ve featured a few of Del-Prete’s illusions before, but this impossible object tattooed on Flickr user bonstance and seen in the book Masters of Deception is still new.

Here’s a great tattoo with a double meaning. Is it a face or a cartoonish man playing saxophone?

Bonus: While it’s little anamorphic, this one might not technically be an illusion. Even so, the details are amazing enough to make it looks completely realistic.

Now, before I sign off, I thought I’d ask you guys about your own tattoos. After all, if you’re a regular reader of Moillusions.com, you just might be the type of person who’s willing to get an illusion tattoo. So, do any of you have illusion tattoos? And if you do, do you have any links to the pictures online? I know I’m not the only one who’d love to see them.

Also, I’m a big fan of giving credit where it’s due, so if you know who did any of the tattoos that aren’t labeled, please leave their names in the comments. Thanks guys!