Comment 7 for bug 707290

Two noticeable things that should be fixed:
1. Holes behaves weirdly in negative contexts, that is to say when the mount hole diameter is larger than the teeth (the teeth are inside the hole) or when the holes border width is too large compared to the place left inside the gear.
2. Some values lead to math errors (very likely a division by zero):
  File "gears-dev.py", line 222, in effect
    a = asin(holes_border/r_outer/2)
ValueError: math domain error

I'll send an example file later today.