The best for me [b]Hermann Grid Illusion[/b] [img]http://listverse.files.wordpress.com/2007/09/232px-hermann-grid-illusion.svg-tm.jpg?w=300&h=300[/img] [i]The Hermann grid illusion is an optical illusion reported by Ludimar Hermann in 1870 while, incidentally, reading John Tyndall’s Sound. The illusion is characterised by “ghostlike” grey blobs perceived at the intersections of a white (or light-colored) grid on a black background. The grey blobs disappear when looking directly at an intersection.[/i]