Five megabytes for the acorn64 rotating box, because it’s a GIF. And a bad GIF that can’t play at its intended speed for most of its rotation, and so has speed jitters (without delving: I presume it’s due to format limitations, as it looks to be using more than 256 colours; see also https://www.biphelps.com/blog/The-Fastest-GIF-Does-Not-Exist). Ugh. `ffmpeg -i acorn64.gif acorn64.mp4` shrinks it to under 350kB, looking about the same except that it now plays smoothly. And will use a lot less power.

(I noticed this because the page was loading unreasonably slowly for unclear reasons. In cases like this, a GIF <img> has a worse failure mode than <video>.)