I love illusions, even from 2011 (Penrose Triangles)
Source: http://www.thingiverse.com/thing:6513

I love illusions, even from 2011 (Penrose Triangles)
Source: http://www.thingiverse.com/thing:6513

See also: http://im-possible.info/english/library/index.html
Look for figure 8 !
Another gimmick: http://www.michaelbach.de/ot/index.html
Cool
Try to catch the energy field 