Do you remember the story of Dr. Jekyll and Mr. Hyde? Dr Jekyll, the famous scientist, is not all he seems, and the other side of his character - Mr Hyde - is, you will recall, a distinctly nasty piece of work.
Continuing the idea of the two sides of the human character, have a look at the picture above. On the left is Dr Angry, and on the right is Mr Calm.
Now, back away from your computer screen. This effect will work at different distances for different people, but you should see the two characters swap over...! As you come closer to the screen again, they revert to their original characters. Spooky or what!
As optical illusions go, we think this is pretty impressive. A short explanation goes something like this. When we look at an object, we can normally see both fine detail and coarse detail. However when we are close, the fine detail will dominate, and when we are further away, we lose the fine detail, and see more of the coarse detail.
Both of the faces you see above are hybrids - each face is actually a combination of two faces. The left hand face shows an angry man in fine detail, but within the picture there is also coarse detail of the calm face. Move away, and you lose the fine (angry) detail, and just see the coarse (calm) detail.
The right hand face shows the calm face in fine detail, and the angry face in coarse detail.
This is based on work by Dr Aude Oliva (MIT) and Dr Philippe Schyns (University of Glasgow). You can read the original paper
This is one of those illusions that just seems to move, even though it is in fact completely still.
This wonderful illusion was created by A.Kitaoka in 2004, who owns the copyright. You can see more illusions on his web SITE
Dragon Illusion
This is a wonderful optical illusion. This little dragon is made out of paper - you simply cut it out and stick it together, and stand it on a table or window ledge. But when you move around, the dragon's head seems to follow you around the room. Have a look at the video, to see what we mean. The effect is really uncanny.
How does it work? If we move around when viewing a solid object, our brain knows how the object we are looking at should behave. However the dragon gives us the wrong clues, because we mis-interpret what its shape is. We assume that the nose of the dragon is pointing out towards us, but in fact the dragon's head is concave.
You can download a copy of the actual dragon and try this illusion for yourself if you wish. This is a PDF file. Right click to download the file. This is a 244k download. Once you have printed the dragon out (a colour printer is best since this is a colour image) then you can cut out the dragon, fold and stick it, and you will be able to see this fantastic illusion yourself. When you print the page out, you will see that the instructions for folding the dragon are included. Please follow these instructions exactly.
The dragon is reproduced here with the permission of the American company ThinkFun (formerly Binary Arts), who sell a wide range of fun toys. Visit the ThinkFun web site to see the wide range of wonderful things they have on offer.
The original version of this illusion involved a piece of paper with this strange spiral on it, and you needed a method of getting the spiral to spin in order to create the illusion.
Now, thanks to the power of the computer, all the hard work has been done for you, and you can run the illusion right here on your screen.
Click here to download a small application file (Optical.exe 22KB). When you have downloaded the file, just double click to run the pinwheel on your computer screen. You need to stare at the centre of the pinwheel for 30 seconds, and then look away from the screen. Wow!
Thanks to Jerry Andrus who invented this illusion, which he calls the Tri-zonal Space Warp! And thanks to Jodi who drew this example of the illusion to our attention.
It may look as if the two arms of the 'X' use different shades of pink, but in fact the whole X only uses a single colour.
Explanation
The difference is that one arm of the X consists of pink squares that replace white squares in the background. Thus these pink squares are surrounded by green squares. The other arm of the X also consists of pink squares, of an identical colour, but in this case they replace green squares in the background, and are therefore surrounded by white squares.
Painters have long known that the way a colour looks in a painting is affected not only by the actual shade of the colour itself, but also by the colours that surround it.
Watch the X in the middle very closely. You should start to see a green dot that rotates around the circle - this dot is an illusion; then you should see see the purple dots disappear.... but they haven't really gone. It is an after image effect, sometimes called a 'negative retinal afterimage' - move your head slightly, and the dots will reappear... amazing or what?
This illusion was designed by Jeremy L Hinton of Bristol, UK, and this illusion - with a lot more explanation and many other illusions as well - can be found at the web site of Michael Bach.
If you liked this illusion, have a look at the Hollow Face Illusion...
Looks like someone has invented perpetual motion - these cogs are certainly never going to stop moving!
Mr. Shebzukhov from Moscow in Russia created this illusion in October 2004, and owns the copyright. This and other illusions can be seen on the 'friends' section of the web site belonging to Mr A Kitaoka, from Japan.
![[screen shot]](http://ccl.northwestern.edu/netlogo/models/models/Sample%20Models/Art/Optical%20Illusions.png)
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I cannot help but stare at it in amazement... the veracity of the illusion is unsettling; You have turned a dull weekend at the office into an exploration of the wonders of the visual centers of the brain. Jim S, Buffalo, NY, USA
