Best of 2025

The blog posts Hacker News loved most in 2025. 238 posts.

Math & Algorithms
179

Rediscovering Quaternions

How do we represent a rotation in 3 dimensions? This is a surprisingly deep question, and one we can learn a lot from. Our goal will be to “rediscover” quaternions from first principles, building them up by exploring different representations and fixing the failures along the way.