Define a curve based on a point collection, and a line to use as a mirror. In 3D the line would be a plane. Now project poles to the axis ( perpendicular to the line ) and then create points on the other side of the axis at the same distance as between the original points and their projections. Finally create a curve from the new poles on the other side of the axis, this curve is a mirror of the first curve. In general, it will be an enantiomorph, that is, identical except for handedness. ... more on Design Patterns CA
RepoMirror Manipulations