Half-edge of an arrangement. Each edge is split length-wise into two half-edges of opposite orientation. Half-edges can be used to traverse an arrangement.
Geometric representation of the edge, for drawing purposes.
The face to the right of this half-edge.
The next half-edge of the face.
The shape that the half-edge originates from.
The edge that was split into this half-edge and its twin.
The half-edge of opposite direction originating from original. This is useful for traversing to a different face.