If you're curious about the source, here's the snapshot:
Codex: https://github.com/stopachka/cscodex Gemini: https://github.com/stopachka/csgemini Claude: https://github.com/stopachka/csclaude
Please try again with Codex on High or Extra High. 5.1-Max nerfed it a bit if you don't use higher thinking.
Thanks. Turns out that shader is a builtin of three.js.