Harvard University,FAS
Fall 2003

Mathematics Math21b
Fall 2003

Linear Algebra and Differential Equations

Course Head: Oliver knill
Office: SciCtr 434
Email: knill@math.harvard.edu

The Droste Effect I, II

A group of Mathematicians at the University of Leiden in the Netherlands has solved a puzzle in one of the pictures of Escher. Click here for getting to the website of that group. The flash movies below were produced using movies found on that page.
Each time frame of the movie is obtained by applying a linear transformation on the picture. The first animationis a simple scaling transformation, the next is a combination of a rotation and scaling (in suitable coordinates). This is called a rotation dilation. For details on how the rotation-dilation is implemented, visit the website.


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