Take two ;)
(It’s back up an d running with a bit of data validation and I realised that I’d over-engineered it – yes, even in 60 lines of code – by storing all the updates in the database when I didn’t need to, so I removed that. Although, in the future, it would be fun to save time-series data so the drawings can be played back in real time.) :)
Play: https://draw-together.small-web.org
Source code: https://codeberg.org/aral/draw-together
Learn how it works: https://ar.al/2024/03/08/streaming-html/