Qwen 3.8 27B names three games from raw weights on laptop
TL;DR
- Running locally, Qwen 3.8 27B correctly identified Pac-Man (72%), Pong (75%), and Breakout (88%) from raw policy-network weights, but failed on Freeway.
- The Pac-Man run took 46m 12s and 43,506 reasoning tokens on Simon Willison's laptop; Pong ran 1h 4m 54s and Breakout 52m 25s.
- The test replicates the no-tools half of 'Sparks of Weight-Space Programming' by Takehi, Teoh, Zhang, and Khattab, originally demonstrated with GPT-6 Astra.
Qwen 3.8 27B, running on Simon Willison's laptop, looked at the raw floating-point weights of four tiny game-playing networks and correctly named three of them.
In a blog post, Willison reports that the model identified Pac-Man with 72% confidence (46m 12s, 43,506 reasoning tokens), Pong with 75% confidence (1h 4m 54s), and Breakout with 88% confidence (52m 25s). It failed on Freeway, calling it 'A simplified Pac-Man-like grid game.' The networks had been trained on simplified 10x10 grid versions of the four classic computer games.
The experiment replicates the no-tools half of 'Sparks of Weight-Space Programming' by Rikiya Takehi, Jayden Teoh, Alex Zhang, and Omar Khattab. The paper's headline claim about GPT-6 Astra, from its abstract: 'Just by looking at the raw weights, GPT-6 Astra can tell what a network was trained to do.' Its second, larger claim is that Astra can natively edit 0.016% of a different model's weights to lift MATH-500 from 7.9% to 48.1%, without writing training loops.
Willison is unimpressed with how those two claims travel together. 'The paper combines two topics that I think deserve to be treated separately,' he writes, noting that spaCy author Matthew Honnibal called the paper misleading for conflating the two and that Sean Goedecke deconstructed the weight-editing example. On his own laptop result, he stays dry: 'a sufficiently experienced human being armed with a notepad and a pencil could get there with enough effort.'
He closes: 'I'm not ready to declare that the age of source code is over and our future involves incomprehensible machines editing their own model weights in incomprehensible ways.'
Shared on Bluesky by 2 AI experts
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There's a buzzy new paper about GPT-6 Astra being able to directly interpret model weights (prompts full of floating point numbers) - I tried it with Qwen 3.8 27B on my laptop and found that, after 45+ minutes, that mode…
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Originally reported by simonwillison.net
Read the original article →Original headline: Qwen 3.8 27B on my laptop can interpret model weights, too