Online versions of The Exploratorium's famous exhibits. From San Fransico's museum of science art and human perception.

Psycholgy Home Page of Hans Irtel ...

This site is about impossible figures, i. e. figures, that can be drawn on paper, but can't be represented in real 3D-world. The father of all impossible figures is Swedish artist Oscar Reutersvard, who was the first to paint impossible triangle. Later Dutch artist M.C. Escher used some impossible figures in his artworks ( Waterfall , Ascending and Descending etc.). Here you ...