The Penrose Stairs Illusion 8/52

Penrose Stairs

I love optical illusions so I thought I would share a few of my favorite and with many people opting to take up 365 day challenges i thought i would try a 52 week challenge in which i will share with you a different Illusion every week. so if you have any you would like me to feature get in touch.

The Penrose stairs or Penrose steps, also dubbed the impossible staircase, is an impossible object created by Lionel Penrose and his son Roger Penrose.[1] A variation on the Penrose triangle, it is a two-dimensional depiction of a staircase in which the stairs make four 90-degree turns as they ascend or descend yet form a continuous loop, so that a person could climb them forever and never get any higher. This is clearly impossible in three dimension

Shortly afterwards, in 1960, Escher produced his paining Ascending and Descending, which contained such a staircase. Penrose and Penrose cited Escher's work as part of their inspiration for creating the staircase, and sent a copy of their paper to Escher. Escher subsequently wrote back to Penrose and Penrose (see Ernst 1992):

A few months ago, a friend of mine sent me a photocopy of your article... Your figures 3 and 4, the 'continuous flight of steps', were entirely new to me, and I was so taken by the idea that they recently inspired me to produce a new picture, which I would like to send to you as a token of my esteem.

Ascending_and_Descending.jpg

However, an impossible staircase was first created many years earlier, in 1937, by Oscar Reutersvärd - unbeknown to the Penroses and Escher.

The Penrose Stairs is an impossible figure (or impossible object or undecidable figure): it depicts an object which could not possibly exist. It is impossible for the Penrose Stairs to exist because in order for it to exist rules of Euclidean geometry would have to be violated. For example, if one were to complete a circuit of the stairs, one would end up back at the same level that one began, even though each flight of the stairs continuously rise (or fall, depending on the direction of travel). It is one of many types of impossible figures which you can search for in the Illusions Index.

What are the best optical illusions you've found on the web? Do you have more amazing examples you don't see here?

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