colorAdjust() is six knobs over the finished frame: brightness, contrast, saturation, gamma, hue (in degrees) and tint (red, green and blue multiplied separately). Each starts where it changes nothing, so it is safe to put in a chain and turn one number at a time.
A look is only a set of those numbers. This example keeps one effect and writes a different set into its uniforms on each click, so changing the look installs nothing and compiles nothing.
Click to change look and Space to switch it off. It goes early in a chain: grade first, and let a palette or a dither decide afterwards which of the graded colours the machine could show.