Much to my surprise, when browsing old(!) versions of this site using the Wayback Machine, I found the source code to the Trigonometron, one of the very first experiments I posted online, back at the beginning of 2002. This predates almost all of my Flash experiments, and indeed I ported this one to Flash a few years after I built the original in Dynamic HTML.
I may do a complete update to this project, as it was built for browsers running at 800×600 resolution following an early-2000s aesthetic, which means tiny, tiny text.
You can View Source of the Trigonometron to see what coding looked like in all its glory, back in 2001 and 2002.