From: darrellvip on 5/25/2009

.
Click on the above source, or 'HERE' for my copy,
to see this set of optical illusions which need
a video for viewing.

.
Click on the above source, or 'HERE' for my copy,
to see this checkerboard optical illusions which
need a video for viewing.

.
Click on the above source, or 'HERE' for my copy,
to see this impossible optical illusion.

.
Click on the above source, or 'HERE' for my copy,
to see this impossible optical illusion.

This movie shows the winner of the Best Visual Illusion
of the Year Contest in 2010 for Meiji Institute for
Advanced Study of Mathematical Sciences, Japan.

In this video, wooden balls roll up the slopes just as
if they are pulled by a magnet.  The behavior of the
balls seems impossible, because it is against the
gravity.  The video is not a computer graphic, but a
real scene.  What is actually happening is that the
orientations of the slopes are perceived oppositely,
and hence the descending motion is misinterpreted as
ascending motion.  This illusion is remarkable in that
it is generated by a three-dimensional solid object and
physical motion, instead of a two-dimensional picture.
Click on either source, or 'HERE' for my copy, to see
this great illusion.