Hacker News on 23 July 2017

• Pev: Postgres ‘Explain’ Visualizer (2016)
• Computational Linear Algebra
• The “Million Dollar Homepage” as a Decaying Digital Artifact
• Status update from the Reproducible Builds project
• How Wi-Fi Works
• A Practical Guide to Tree-Based Learning Algorithms
• Printed Solar Panels for Less Than $10 a Square Metre
• What are covariance and contravariance?
• How do I know if I'm good at programming?
• TLS 1.3 in enterprise networks