THE ILLUSION OF A SEPARATE SELF: Your sense of self —something or somebody separate from the rest of the universe (and separate from the general flow of experience)—is like your perception of white on a color computer monitor. If you look closely with a magnifying lens, there is no white on your screen, only red, green & blue pixles. White is an illusion created when 3 other things are confused, mixed together. "I am", the separate self, is a closely analogous illusion. — Greg

Just as RED GREEN and BLUE light
mixed together—
create WHITE on your computer monitor ,
BODY SENSATIONS, MENTAL IMAGES & INTERNAL TALK
(a mixture of thoughts & feelings) create your concept & sense of
SELF

This is the meaning of "not-self" or "no self" (anatta): The sense of self, "I am", is like a WHITE spot on your computer monitor. It exists only if you don't look very closely. If, with the "microscope" of mindfulness, you look very closely, the "conceit of I am" vanishes and is replaced with the components that created the illusion. The components are your thoughts (inner talk & mental images) and feelings, combined with the visual, auditory and tactile senses. These components can be represented by three "primary colors" of experience: BODY, IMAGE and TALK (BIT). These 3 primary colors of experience create the illusion of self, just as the 3 primary colors of light (RGB) create the illusion of white. BIT is analogous to RGB. “I am” is analogous to “white”.

thanks to Shinzen Young