Joaquim Alves Gaspar captured this photograph of a man walking in a tunnel holding a camera.  The picture was taken at São Martinho do Porto on the west coast of Portugal.  It is uncertain whether the man is approaching the camera or walking away from it.  Can you tell?

This picture was found on Wikimedia Commons.

In 1754, William Hogarth produced the following engraving for a pamphlet about linear perspective.  It features many deliberate perspective problems.  How many can you find?

Continue reading the full post for a short list of some of the problems with this picture.

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This is a pretty powerful example of a motion illusion.  Do the green, purple, white and black “tubes” appear to be moving in a swirling motion?  It almost appears as though the objects are made of wax and melting on the screen.

Tracy Lee Stum is an internationally recognized chalk artist / streetpainter who specializes in large interactive 3D chalk art.  Her painting below, titled “Escape of the Mummy”, was created in 2008 for the Youth in Arts Street Painting Festival in San Rafael, California.  The painting took 2 1/2 days to complete and measured 12 feet wide by 12 feet tall upon completion.  Stum took inspiration from the Indiana Jones and Mummy movie franchises when coming up with this concept.

More works from this artist can be viewed at TracyLeeStum.com.

A tiger can be seen in the foreground of the image below.  Can you locate the hidden tiger in this painting by American artist Rusty Rust?

More of Rusty’s paintings can be viewed on his personal website at Rusty Art.

In the video below, two colored bars (feet) move horizontally across the screen.  One is red and the other is blue.  Stare at the area marked “Look Here” and watch what happens as the bars move across the two different backgrounds.  As they travel across a background that is striped, they appear to be out of sync with one another as if they are moving in a “stepping” motion.  When the background changes to a solid color, however, their true movement is revealed.  Each of the bars is moving at the same pace throughout the entire video.

This illusion was first described by Stuart Anstis from the University of California, San Diego.

To call this stairway construction an engineer’s nightmare would be an understatement.    Start on the pathway at the bottom and climb down the stairs.  As you do so, you actually are moving up the building.  Be thankful that you are not the person tasked with constructing this bizarre series of stairs.

To see more impossible geometry, fractals and other works from Jos Leys, please visit his site.