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Making the impossible possible | Construction of the Penrose Triangle

Author:Max Hoffmann



The Penrose Triangle (also tribar) is a well-known optical illusion, which cannot exist in reality. But we will find out that it is all a matter of perspective. Use the following plan sketches to reconstruct a tribar in GeoGebra 3D.



You can do the construction either in the following web applet or directly in GeoGebra. Here are two more tips for the construction:
  • The command Toolbar Image can be used to complete points that form a plane polygon into a prism that passes through another point.
  • It can be helpful to enter the coordinates of individual points manually via the algebra window.
Under the following links, you will find a finished tribar constructed in GeoGebra.

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