Unicorn, Pelican, Middle-earth: OpenAI Co-founder Karpathy Seeks the Next AI Vibe Test

Andrej Karpathy, co-founder of OpenAI and now working at Anthropic on pre-training research since May 2026, had the AI model Claude Opus 5 render the opening of Tolkien's 'Lord of the Rings' as a 3D scene for the browser. The model worked for about two hours with a budget of one million tokens (about ten dollars) and was to render everything in Three.js, a graphics library for 3D in the browser. Karpathy published the source code online so others can play and rebuild the scene. He argues that the well-known 'Pelican test' is slowly exhausted; that fun benchmark by Simon Willison asks a model to draw an SVG graphic of a pelican on a bicycle, deliberately absurd so the motif is not in training data. The idea is older: Microsoft in 2023 used GPT-4 in the Sparks of AGI paper to draw a unicorn in TikZ, interpreting it as a sign of spatial understanding; GPT-4 then was trained exclusively on text data, unlike multimodal models today. Karpathy calls the result rough but fun; the voice was provided by Eleven Labs, and the model placed and animated objects itself. He says no one would build such worlds by hand, and with a model it is almost free. He sees potential for custom game worlds where users could be placed as supporting or main characters. A remaining problem is that the model cannot watch its own video and had to use screenshots, leading to errors. Other users have had Opus 5 write entire browser games, from first-person shooters to Minecraft clones. Neither is a hard measurement but rather vibe checks.