Overlay you can draw and replace:
- shaders/textures/lsd_overlay.png

It is bound to the shader as: lsdOverlay (see shaders.properties: texture.final.lsdOverlay)

Recommended drawing:
- Transparent background (PNG with alpha)
- Dark ink lines (black/purple), semi-transparent edges
- A "trip doodle": eyes + spiral + crooked smile + a few wavy lines
