I created a shader quine, a fragment shader without input (textures or models) that produces a copy of its own source code as its output, on Shadertoy. You can find (the full source of) the fragment shader here: https://www.shadertoy.com/view/MlGcRz. The ‘trick’
An organic-looking SDF scene in a single, fully procedural, fragment shader. The scene is modelled for this specific camera viewpoint and lighting setup.