* Use turbo mode (<Shift> key + Green Flag) Choose any number between 1 and 100 for the randomness. My favorite is 40. 20 random points (at the centre of each bright spot) are placed on the stage. A Voronoi diagram colours each pixel on the stage with its colour depending on the closest point with some added randomness.
@Scratch-Minion and @Rocket-Flier for their projects, I only made a small tweak.