LiveGraphics3D Example:
Some Ambiguities



Something Like Two Cubes

Changing the point of view offers the possibility of resolving ambiguities sometimes occuring in two-dimensional graphics. This (classical) example demonstrates an intentional ambiguity: One of the cubes is actually "inverted" which becomes obvious as soon as you start rotating it (by dragging with the left mouse button pressed).

There are many even more amazing examples of this effect, but most of them are likely to lead to problems with the hidden surface algorithm used in LiveGraphics3D. Nonetheless LiveGraphics3D is one of the few tools to demonstrate this kind of objects.



Escher's Triangle

Ambiguities may also arise between realizable and impossible figures like Escher's triangle shown here. (This example is taken from a page created by Hans Wilding.)



A Reflecting Sphere

This example shows an ambiguity, too: An object is copied and transformed to give the illusion of the existence of a reflecting sphere. However the trick breaks down as soon as the objects are rotated. (Thus LiveGraphics3D should not be used to show this picture!)



Martin Kraus, March 11, 1999