Agreed, and some controls that allow you to specify the radius of a gear instead of drawing it would help, too. I spent a long time trying to draw two gears with the same number of teeth on my ^#$(@#! trackpad. :)
Also, there's a UI limitation with snapping concentric gears together: you can snap a small gear onto a larger one, but not the other way around. This seems to make it impossible to add a pair of concentric gears whose smaller gear is meshed with the edge of an existing gear.
But overall, great project with very pleasant casual interaction. Would be interesting to see what you plan to do with it.
Also, there's a UI limitation with snapping concentric gears together: you can snap a small gear onto a larger one, but not the other way around. This seems to make it impossible to add a pair of concentric gears whose smaller gear is meshed with the edge of an existing gear.
But overall, great project with very pleasant casual interaction. Would be interesting to see what you plan to do with it.