I represent a half-edge within a subdivision.

	enumeration
	edgesDo:stamp: markExteriorEdges: triangleEdges:do:

	initialize-release
	id:owner:

	printing
	printOn:

	private
	ccw:with:with: collectQuadEdgesInto: displayOn:at:withSize:stamp: isLeftPoint: isPointOn: isRightPoint: quadEdgeClass triArea:with:with:

	topological operators
	connectEdge: deleteEdge spliceEdge: swapEdge

	accessing	top
	center
	classificationColor
	classificationIndex Return the classification index of the receiver
	destNext Return the next ccw edge around (into) the destination of the current edge.
	destPrev Return the next cw edge around (into) the destination of the current edge.
	destination
	destination:
	end
	inverseRotated Return the dual of the current edge, directed from its left to its right.
	isBorderEdge
	isBorderEdge:
	isExteriorEdge
	isExteriorEdge:
	isInteriorEdge
	isInteriorEdge:
	leftNext Return the ccw edge around the left face following the current edge.
	leftPrev Return the ccw edge around the left face before the current edge.
	length
	next:
	nextBorderEdge
	origin
	origin:
	originNext Return the next ccw edge around (from) the origin of the current edge.
	originPrev Return the next cw edge around (from) the origin of the current edge.
	quadEdge
	rightNext Return the edge around the right face ccw following the current edge.
	rightPrev Return the edge around the right face ccw before the current edge.
	rotated Return the dual of the current edge, directed from its right to its left
	squaredLength
	start
	symmetric Return the edge from the destination to the origin of the current edge.
	timeStamp

	enumeration	top
	edgesDo:stamp:
	markExteriorEdges:
	triangleEdges:do: Evaluate aBlock with all edges making up triangles

	initialize-release	top
	id:owner:

	printing	top
	printOn: Append to the argument, aStream, a sequence of characters that identifies the receiver.

	private	top
	ccw:with:with:
	collectQuadEdgesInto:
	displayOn:at:withSize:stamp:
	isLeftPoint:
	isPointOn: A predicate that determines if the point x is on the edge e. The point is considered on if it is in the EPS-neighborhood of the edge
	isRightPoint:
	quadEdgeClass
	triArea:with:with: Returns twice the area of the oriented triangle (a, b, c), i.e., the area is positive if the triangle is oriented counterclockwise.

	topological operators	top
	connectEdge: Add a new edge e connecting the destination of a to the origin of b, in such a way that all three have the same left face after the connection is complete. Additionally, the data pointers of the new edge are set.
	deleteEdge
	spliceEdge: This operator affects the two edge rings around the origins of a and b, and, independently, the two edge rings around the left faces of a and b. In each case, (i) if the two rings are distinct, Splice will combine them into one; (ii) if the two are the same ring, Splice will break it into two separate pieces. Thus, Splice can be used both to attach the two edges together, and to break them apart. See Guibas and Stolfi (1985) p.96 for more details and illustrations.
	swapEdge Essentially turns edge e counterclockwise inside its enclosing quadrilateral. The data pointers are modified accordingly.

	accessing	top
	splice:with: This operator affects the two edge rings around the origins of a and b, and, independently, the two edge rings around the left faces of a and b. In each case, (i) if the two rings are distinct, Splice will combine them into one; (ii) if the two are the same ring, Splice will break it into two separate pieces. Thus, Splice can be used both to attach the two edges together, and to break them apart. See Guibas and Stolfi (1985) p.96 for more details and illustrations.