It started as a small explanation on the basics of Bezier curves in 2011 and then kept growing until it's basically a full book now, hitting hacker news every year/half year, and getting lots of thanks for having made it by a very diverse crowd - from kids doing homework to engineers at software companies who have a question not covered by the material (yet).

It's been a mostly low effort investment and I could have just as easily not bothered, but just adding small bits at a slow pace parts of on the internet: five years of improvement would not have happened if I'd simply not bothered, and now there is an amazingly popular free resource for this material easily findable online.