ARC support for ellipse draw

[Tim Wessman]

I was thinking about this today. How would people feel about this?

Currently we have:
ARC(G, x, y, r, [[∠1, ∠2],[color]])

How would you feel about making it as such:
ARC(G, x, y, r|(r1,r2), [[∠1, ∠2],[color],[color]])

Basically, add in a second color for fill and border (like rect), but more importantly allow ellipse drawing if you give a pair of r values in a complex.

There isn't a way that I can see to support ellipses without either a) this described method or b) a separate command, without potentially introducing backwards compatibility issues.

Better suggestions?