The YIQ block is a reference algorithm using a simple model of color brightness. It decides if the color is "bright" or "dark" and then makes the text black or

The YIQ block is a reference algorithm using a simple model of color brightness. It decides if the color is "bright" or "dark" and then makes the text black or white according to that. It's there to demonstrate how the neural net can (if trained right) outperform the simpler model. But yes, the background colors are random. I agree it could use a bit of explanation.