General questions

[SupremeGrandRuler]

1) What happens if the end value of a loop is smaller than its start value?

2) Is it possible to create circular regions, perhaps even with vjass?

 

[Ralle]

1)
I believe the loop will not iterate even once.

 

[defskull]

1) What happens if the end value of a loop is smaller than its start value?

I think you have a tool named "World Editor" that allows you to self-test experiment like this.

Yes, it will not iterate at all.

 

[Troll-Brain]

Circular regions are possible if you use many cells, basically they are just mini rects of size 32*32.
It's only available on (v)Jass and it will be an approximation of a circle, the smaller the circle will be, the more innacurate it will be.

Now it depends what you want, you can also just check periodically a distance.