The mind-boggling optical illusion that makes parallel lines appear slanted

  • The horizontal bars on the image look like they're bending or are at an angle
  • But  a closer look reveals that the lines are actually straight and in parallel rows 
  • The alternating target patterns, rows and colors, all combine to trick the brain into thinking the bars are slanted instead of straight
  • The illusion, made by magician and illusionist Victoria Skye, is based off the 'café wall illusion,' originally observed on tiles on the facade of a café in Bristol, UK 

By Cecile Borkhataria For Dailymail.com

Published: 16:46 EST, 8 August 2017 | Updated: 01:34 EST, 9 August 2017

Do the horizontal bars on the image below look like they're bending or are at an angle?

If you think they are - look closely again. 

The lines are actually straight and in parallel rows, and the alternating target patterns, rows and colors, all combine to trick the brain into thinking the bars are slanted. 

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The illusion was made by Victoria Skye, 58, a professional magician and illusion artist from Roswell, Georgia. The key to the illusion are the black and white diamond 'targets' at each intersection. When looking at the lines vertically, one can see that the squares that make up the diamond alternate their position. 'The alternating targets create the effect,' said Skye 

The illusion was made by Victoria Skye, 58, a professional magician and illusion artist from Roswell, Georgia. 

Skye told the DailyMail.com that the illusion is based off the café wall illusion, and that she plans to submit her illusion to the 'Best Illusion of the Year Contest' next year. 

The key to the illusion are the black and white diamond 'targets' at each intersection.

When looking at the lines vertically, one can see that the squares that make up the diamond alternate their position.

'The alternating targets create the effect,' said Skye. 

'I developed my version of the illusion by reviewing many dozens or hundreds of visual illusions over the years. 

'In my version of the famous Café-Wall illusion, I have mixed together both the original Café-Wall illusion that was made famous by Richard Gregory - and which showcases the brickwork laid on the wall of a café in Bristol, England - with the work of Akiyoshi Kitaoka, who has developed a number of different versions using the same underlying effect,' said Victoria Skye, the creator of the illusion  

'In my version of the famous Café-Wall illusion, I have mixed together both the original Café-Wall illusion that was made famous by Richard Gregory - and which showcases the brickwork laid on the wall of a café in Bristol, England - with the work of Akiyoshi Kitaoka, who has developed a number of different versions using the same underlying effect,' said Victoria Skye, the creator of the illusion  

'In my version of the famous Café-Wall illusion, I have mixed together both the original Café-Wall illusion that was made famous by Richard Gregory - and which showcases the brickwork laid on the wall of a café in Bristol, England - with the work of Akiyoshi Kitaoka, who has developed a number of different versions using the same underlying effect. 

'I asked Stephen Macknik and Susana Martinez-Conde - illusion neuroscientists and coauthors of the upcoming book "Champions of Illusion," about the effect and they informed me that this class of illusions is called the “twisted cord” class of illusions, because the first version - by the Scottish physician James Fraser - was in the form of a twisted cord. 

Victoria Skye's café wall illusion falls in the class of illusions is called the 'twisted cord' class of illusions, because the first version - by the Scottish physician James Fraser - was in the form of a twisted cord (pictured) 

Victoria Skye's café wall illusion falls in the class of illusions is called the 'twisted cord' class of illusions, because the first version - by the Scottish physician James Fraser - was in the form of a twisted cord (pictured) 

'The reason the illusion exists has to do with the (way the) white and black edges interact in opposite directions along the straight edge, tricking the brain into thinking there is a slant in the line.

'If you blur the image, the effect disappears… because you cannot resolve the tiny white-black interactions once they are blurred, so the brain is no longer led down the garden path.'

The classic version of the café wall illusion (pictured) is produced by rows of black and white rectangles, where each 'brick' is surrounded by a line of 'mortar' - grey lines

The classic version of the café wall illusion (pictured) is produced by rows of black and white rectangles, where each 'brick' is surrounded by a line of 'mortar' - grey lines

The classic version of the café wall illusion is produced by rows of black and white rectangles, where each 'brick' is surrounded by a line of 'mortar' - grey lines. 

According to New World Encyclopedia, the mortar lines should ideally be a shade somewhere between the two tile colors. 

When the tiles offset by half a tile width in each successive row, the horizontal lines seem to slant diagonally.  

Another of Victoria Skye's illusions, entitled 'Age, It's All In Your Head.' Tilting the photo distorts the shape of the head and facial features to create the illusion of an actual age progression and regression. The image is of Skye's father

Another of Victoria Skye's illusions, entitled 'Age, It's All In Your Head.' Tilting the photo distorts the shape of the head and facial features to create the illusion of an actual age progression and regression. The image is of Skye's father

If the mortar lines are removed, then the illusion no longer works. 

The lines are perceived as running diagonally because of the way neurons in the brain interact with each others. 

Different types of neurons react to dark and light colors, and because of the way the dark and light tiles are placed, different parts of the grey mortar lines are perceived as lighter or darker by the retina. 

Another of Victoria Skye's illusions, entitled 'Age, It's All In Your Head.' The illusion made the top 10 in the 2014 Best Illusion of the Year Contest. It begins as a normal photograph and then is tilted backwards and forwards to create opposite vanishing points. The tilting distorts the shape of the head and facial features to create the illusion of an actual age progression and regression. The image is of Skye's father

The illusion was first reported by Dr Richard Gregory, a professor of neuropsychology at the University of Bristol, Dr Priscilla Heard, an experimental cognitive psychologist at the University of the West of England. 

In 1979, a member of Gregory's lab observed the unusual visual effect created by the tiling pattern on the wall of a café at the borrom of St Michael's Hill in Bristol, United Kingdom. 

The café was tiled with alternate rows of offset black and white tiles, with visible mortar lines in between . 

THE CAFÉ WALL ILLUSION

The café wall illusion was first reported by Dr Richard Gregory, a professor of neuropsychology at the University of Bristol, Dr Priscilla Heard, an experimental cognitive psychologist at the University of the West of England. 

In 1979, a member of Dr Gregory's lab observed the illusion created by the tiling on the wall of a café at the bottom of St Michael's Hill in Bristol, United Kingdom.

In February 2010, Professor Richard Gregory visits the Bristol café wall where, in 1979, his lab member first spotted the café wall illusion 

In February 2010, Professor Richard Gregory visits the Bristol café wall where, in 1979, his lab member first spotted the café wall illusion 

The café was tiled with alternate rows of offset black and white tiles, with visible mortar lines in between. 

The team's findings were published in a 1979 research paper in the journal Perception. 

The effect is also sometimes referred to as the Munsterberg illusion, because the illusion was previously reported in 1897 by Hug Munsterberg, who called it the 'shifted chequerboard figure'. 

The illusion has also been used in graphic design, architectural and artistic applications.  

The image above shows a picture of a building in Melbourne, Australia designed in the style of the café wall illusion. The building  is part of Melbourne's Digital Harbour Port

The image above shows a picture of a building in Melbourne, Australia designed in the style of the café wall illusion. The building  is part of Melbourne's Digital Harbour Port

 

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