Click the green flag and wait! This runs faster on Phosphorus: https://phosphorus.github.io/app.html?id=270814575&turbo=false&full-screen=true Press space to change colors.
Explanation: A fragment shader is a program that edits how something looks by scanning an area pixel by pixel and correcting each color. This particular shader scans the screen to find any light sources (the orange things you see at the beginning) and diffuses a monochromatic color's brightness. In layman's terms, it makes it super bright.