"Things You Wouldn't Know If We Didn't Blog Intermittently."
Interesting but seems to depend on serifs on 5 and 9 and European notation on 7. But cute.
A long time ago I was at a multicultural fair, and I was told that this was how we got our Arabic numerals. I think I even still have the original handout from 1990...
If it is the actual origins of the digits you want (and I don't think the angles diagram is puporting to be the origin so much as an interesting observation/construct), then there is a mich simpler explanation: laziness(definitely for the gigits 1, 2, and 3, maybe for four. Beyond that it gets a bit contrived).First, you need to look at the original indian numerals. See the diagram under Origins here.Then imagine a lazy writer not lifiting the pen properly between strokes in making the simple 1, 2 or 3 dash representations of those digits (and maybe 4). See this diagram of indian digits I just made.
Oops... sorry about the typos!
Very interesting diagram, Mark. Even the "5" isn't too hard to extrapolate, and 6 and 7 are obvious.