Here is a full solution, there might be a simpler or cleaner way but this works.
You would just modify the numbers in the list of distances in the Code Block to correspond to the offset of each line:
curves = {North,East,West,South};
distances = {10,10,20,12};
vecs = curves.NormalAtParameter(0.5);
pts = curves.PointAtParameter(0.5);
points = pts.Translate(vecs.Reverse(), distances);