The first year, there wasn't a rule against multiple accounts. I remember running several accounts and constantly flicking between them. After that, it was decided that people should only have one account, and that rule was introduced. So it's hard to really assess the number of people participating in that year. If the second year was longer like I think it was, that would also explain more people participating.

Just looking through the archive, the 2023 canvas was four times as big (1000x1000). It was quite empty at the end despite all the extra accounts people were using.

In 2024 the canvas started at 500x500. At a certain point in the event, the canvas doubled in size, opening up a whole extra canvas, making a 1000x500 canvas. It was fuller but still had a lot of gaps at the end.

2025 was 500x500, and was pretty nicely filled in, some whitespace but not that much.

2026 is definitely the most complete. You can zoom in randomly and almost any spot you look it looks like every part has been filled in with something. It was 500x500 as well, which seems like the right size for the event.

I agree it's nice to not have everyone try to fill in flags that are way too big or that stretch out to overrun other art.