I enjoyed that the Union Flag just gets its own 'preset' - the fact that it's still presiding over a large handful of others makes it a very efficient decision compared to trying to tease out all the necessary shapes to reconstruct it.
I'll admit, I was hoping for some geometric approximations for countries like Brazil, though.
This scheme is OK but not OK. You note the Brazil flag and that's a great example along with the likes of the UK and the US too.
The Brazilian flag is nominally "quite" simple: Green with a yellow/gold parallelogram/rhombus with a blue circle ... then there is the white band and stars. Absolute nightmare to classify.
I thought the UK flag was a bit of a challenge and I remember an art class 50 odd years ago, trying to paint the bloody thing. Little did I know at the time about how Aussies and Kiwi worriers and co would fare! Won't someone think of Hawaiians: their state flag is not something you depict for a quick laugh!
I suppose the US flag is arguably the hardest to depict: Those stars would take ages to draw/paint/dribble. I imagine kids get a box of stars to stick on their depictions in art classes in the US.
What's really hard, together with the quantity of them is that they're white! I haven't actually seen many star stickers used, but agree that's a great idea.
Often, when the Flag's depicted in kids' art, paints or paint pens are used, since 'negative space' stars would take forever to do with a blue marker or pencil but is quicker to paint on top of blue. And there's a great deal of artistic license used in terms of their size and color. Or on a small flag, just a lot of tiny white dots!