Simple question, which way is the Optical Spy Penny Farthing cycle going, forwards or backwards?

Also check out the McGurk effect, which is another astonishing audible illusion and the Sheppard Tone illusion which is shown near the bottom of the home page.

Salvador Dali's original Swans Reflecting Eleephants.

Our modification to Dali's original

Which of these three arcs will make the largest complete circle? Click the optical to find out.

If you are an Optical Spy regular you will be aware that I am a big fan of Ben Heine. When Ben uploads photo's from his travels around the world I am always inspired to make an animation. This latest one was great fun making. Hope Ben likes it.

Did Eve really make Adam eat the forbidden apple? Well this optical illusion looks like they both had a bite!

Click or hover over picture to reveal. Image source brettstanleyphoto.com

These two cars look completely different sizes because your eyes see the 3D perspective you would normally associate with a 2D photograph. But the actual 2D size here is exactly the same. Original image source unknown.

Here is the first photograph of an Irish leprechaun. With his ginger beard, crumpled up nose and pursed lips he looks a little strange. Just hover over or click the picture to see what is really going on.

According To legend, Robert Chang painted a picture of a Japanese girl called the Melancholic Princess. He then posted it on the Internet and-committed suicide.
Some people who saw the picture declared that, if you look at it for a short while the picture starts to move, or age, or smile, or change - everyone saw something different . What do you see? Let us know below.

This upside down illusion is of our favourite Tech Guru Walt Mossberg. If you'de like to read any of Moss's excellent work you will find it here recode.net

I've got a great illusion for you today. You will see above a grid with two black and white blocks moving from right to left and back again. It appears that the blocks are not moving smoothly, but stepping from one line to the next. This is only an illusion. If you press the add words button at the bottom you will see that when we put the optical spy words on the blocks they now flow smoothly back and forth. But the movement of the blocks hasn't changed at all, it just overrides the illusion. Press remove words button to reset.

Are the reds in both optical spy letters the same color? Just click on the optical to find out.

As an update to our grid illusion we have designed the same grid with dots. The only difference between the checker boards are the dots, the red and black squares are always the same.

Here is a scary illusion. Firstly, keep your mouse away from the image and let it just rotate. Get as close as you can and watch it rotating for about thirty seconds. Then without taking your eyes off of it move your mouse over the image. Then just enjoy!. It also works if you look at anything else, try looking at the back of your hand.