I never really thought much about this before.  Why do we do this `glueTrail`?  E.g. what if the sweep angle is 3/2 turn?  Doing `glueTrail` is very strange in that case.  It seems the most consistent thing to do is to always generate a `Line`, which may wrap around multiple times in the case of a sweep angle greater than 1 turn (or less than -1 turn).  I could imagine actually being able to do useful things with such arcs, e.g. using them to parameterize animations, or applying a transformation that scales along with the parameter in order to create a spiral, etc.