A 75kb single-file 3D fractal explorer built in 2 hours with GPT 6 and Opus 5.5

paintoshi · reddit · 2026-09-29

A developer used GPT 6 Astra (medium) plus Opus 5.5 to build a browser-based 3D fractal world explorer in about 2 hours: a single 75kb HTML file, zero external libraries, running on desktop and mobile.

Fractals are mapped to pixels in real time via GPU ray marching—no textures or meshes needed, minimal memory, infinite exploration. The build started in Astra and switched to Opus 5.5 for optimization after running out of tokens, as a stress test of both models' math and shader capabilities.

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