Hacker News on 21 June 2021

• Japan's government plans to encourage 4-day workweek, but experts split
• Ask HN: I was hit with a patent troll lawsuit, how do I deal with it?
• Git undo: We can do better
• Fluid Paint
• PNG files can be animated via network latency
• Internal Amazon documents shed light on how company pressures out office workers
• USC professor’s DIY online teaching hack to engage students goes viral (2020)
• Yggdrasil – Early-stage implementation of an end-to-end encrypted IPv6 network
• Did Windows 10 slow down with each feature update?
• LibreCellular