mixtures compounds and elements

"A mixture is like the picture itself, a combination of coloured
image pixels (an image pixel is one square of pure colour). A compound is like one of the image pixels that make up the picture. An element is like one of the screen pixels that make up the image pixels -there are only three colours of screen pixel: red, green and blue. All the pictures on your TV or computer screen ultimately come from just red, green and blue and you cannot break these pixels into to any smaller pieces of other colours."