Some additional stuff.

The "crazy circles" illusion is a popular cinematic visual illusion. However, it is not strictly an illusion. To see why read here.

Akiyoshi Kitaoka has devised many amazing color illusions. However, they are not really illusions in the strict philosophical sense. Why? Check here.
You can also read this article on the same topic: The color of consciousness.

Afterimages are yet another interesting visual phenomenon. However there has been some persisting confusion on the issue. You may check some simple but significant experimental results here. (November 2015). You can also read this article on the same topic: The color of consciousness.

Are neurons any better than ripe strawberries in being red? Check here.

Reality, knowledge, and experience in one diagram. Check here.