Ask HN: What interesting tech videos have you watched recently (3 – 6 months)?

If the question seems too broad, I can narrow it down by specifying some tech topics. But for this first cut, I thought of leaving it open, just qualifed by "tech". One reason for that is because that there is often cross-pollination of ideas when you read or watch topics from other fields than your own (main ones). But also because it's fun to read/watch stuff outside your own areas anyway, regardless of the benefits ...