Mike Bostock made D3 when the browser was still a joke. He built bl.ocks when people needed somewhere to share their work. Now he's building Observable — reactive notebooks with an AI that actually looks at what it made. In this episode: the three-GIF bar chart that launched 25 years of viz, why open source needs both intrinsic and extrinsic motivation, and why an agent that can't see its own output is likely to be confidently wrong.

What's Inside

• The 1998 visualization library that could only make bar charts
• Why D3 hit #3 on GitHub, and what killed the gallery
• What spreadsheets got right that notebooks ignored for years
• "The agent can lie with text, but not with code"
• Why Observable scrapped canvases and went back to notebooks
• The penguin dataset that exposes AI
• Strength training, tennis mind games, and a resurrected Stanford game