Offset a curve twice and connect the results.

Input parameters:

1. Cr → Curve to widen.
2. Wi → Widening thickness.
3. Pl → Optional offset plane.
4. Rj → Use arcs for kink offsets.
   •  True → Round
   • False → Sharp
5. Rc → Use semi-circles to connect the results.
   •  True → Round
   • False → Flat

Output parameters:

1. Cr → Widened curve.