Hi Mike,

>>Tell me, is there any reason why vMagnitude (Large circle radius) can be negative, so a range of -30 to +30 instead of simply 0 to 30?<<

Yes the range could be simply 0 to 30, but if you dial from start to finish you'll see that the extremes (-30, 30) are not identical.

It is similar to curves/polygon node setting "TYPE" "inscribed" / "circumscribed".

Have a great weekend

James