My summer at Recurse Center: implementing DEFLATE, building agent sandboxes, and starting a math group

What I did at Recurse Center

The author spent a summer at Recurse Center, a programming retreat in Brooklyn. He joined several study groups: in Agentic Adventures, he and a partner built a remote sandbox for a vibecoding agent with dangerously-skip-permissions; they trained a tiny Shakespeare-style text predictor with minGPT and did LoRA fine-tuning for more conversational output. The Practical Deep Learning group worked through the first half of fastbook, from classical ML to building neural nets. Math Monday was a discussion group he co-started—they solved Project Euler problems, drew fractals, built Voronoi-based games, and tried the Rocq proof assistant. His most hardcore project: implementing a DEFLATE decompressor in Rust straight from RFC 1951, using LZ77 + Huffman coding, debugging by writing out bit sequences by hand. He also finished his mini-language dodo, writing the recursive match statement himself while using LLMs only for specs and tests. The post doesn't say whether he finished the emacs magit plugin.