What are the key takeaways from this CoRecursive episode?

Key insights include: **Technical Implementation:** Build six emulators progressing from Mathematica to Rust, achieving 200,000x speed improvement from initial tenth-second-per-move to five microseconds per core through optimization.; **Cloud Computing Costs:** AWS 72-core instances cost more than budgeted when games run longer than expected due to single-threaded file operations becoming bottlenecks at scale.; **Heuristic Development:** Quiescent lookahead (bird-in-hand heuristic) dramatically outperforms brute force approaches, achieving 148 points with 100,000 beam width versus 86 points with 25,000,000 width.

What did David Freibert discuss on CoRecursive?

Two friends obsess over Hatetris, a malicious JavaScript Tetris variant, spending months and hundreds of dollars to break world records using beam search algorithms. Key topics include: **Technical Implementation:** Build six emulators progressing from Mathematica to Rust, achieving 200,000x speed improvement from initial tenth-second-per-move to five microseconds per core through optimization.; **Cloud Computing Costs:** AWS 72-core instances cost more than budgeted when games run longer than expected due to single-threaded file operations becoming bottlenecks at scale..

How long is this episode of CoRecursive?

This episode is 48 minutes long. SignalCast provides an AI-generated summary so you can get the key insights in about 3 minutes.

CoRecursive

Story: Hatetris - Obsession, Friendship, and World Records

March 3, 2025

48 min episode · 2 min read

David Freibert

Episode

48 min

Read time

2 min

Topics

Fundraising & VC, Psychology & Behavior

AI-Generated Summary

Published Dec 19, 2025

Key Takeaways

✓Technical Implementation: Build six emulators progressing from Mathematica to Rust, achieving 200,000x speed improvement from initial tenth-second-per-move to five microseconds per core through optimization.
✓Cloud Computing Costs: AWS 72-core instances cost more than budgeted when games run longer than expected due to single-threaded file operations becoming bottlenecks at scale.
✓Heuristic Development: Quiescent lookahead (bird-in-hand heuristic) dramatically outperforms brute force approaches, achieving 148 points with 100,000 beam width versus 86 points with 25,000,000 width.
✓Community Knowledge Sharing: Publishing methods openly accelerates progress across competitors - each record holder built upon previous approaches, creating collaborative advancement despite competitive environment.

What It Covers

Two friends obsess over Hatetris, a malicious JavaScript Tetris variant, spending months and hundreds of dollars to break world records using beam search algorithms.

Key Questions Answered

•Technical Implementation: Build six emulators progressing from Mathematica to Rust, achieving 200,000x speed improvement from initial tenth-second-per-move to five microseconds per core through optimization.
•Cloud Computing Costs: AWS 72-core instances cost more than budgeted when games run longer than expected due to single-threaded file operations becoming bottlenecks at scale.
•Heuristic Development: Quiescent lookahead (bird-in-hand heuristic) dramatically outperforms brute force approaches, achieving 148 points with 100,000 beam width versus 86 points with 25,000,000 width.
•Community Knowledge Sharing: Publishing methods openly accelerates progress across competitors - each record holder built upon previous approaches, creating collaborative advancement despite competitive environment.

Notable Moment

Their AWS bill doubled when the game performed better than expected, forcing them to watch costs climb while unable to stop the process without losing everything.

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