The most incredibly boring work of mankind so far? It would probably be those mosaic portraits that are constructed of tiles, each of which is a different, tiny image of something. The question: WHY, for the sake of all goodness and kindness, WHY??? Usually almost as close to that boring, and yet part of a very long-standing artistic tradition, is the large image that is formed by unrelated smaller elements of a totally different image. There are endless examples on the Internet, almost all of a stunningly pointless and impossibly uninteresting nature. And what does any of this have to do with optical illusions? Precisely nothing, and yet Internet illusion sites are loaded with such images. Well, having said that, here are a few such images that are not too bad. I like the portrait of a girl formed of flowers and a butterfly, as seen above. As for some others:

Illusion 1, Illusion 25, Illusion 50, Illusion 75, Illusion 110, Illusion 120, Illusion 130,

Next Illusion in the set?

An extremely nice collection of very colorful illusions, many of which were new to me.

Individual Project LITE pages are linked elsewhere on these illusion pages, but here's the full directory.

Individual ZONEFLASH animated illusion pages are linked elsewhere on these illusion pages, but here's the full directory.

Although Akioshi Kitaoka's illusion pages are randomly distributed, like the ones you are looking at now, there actually is an index, here.

A long article on illusions, with dozens of animated illustrations.