A procedure for computing the symmetric difference of regions defined by polygonal curves

Given any two regions A, B in the plane, defined by polygonal (simple, closed and oriented) curves, associated with their respective boundaries, we describe a procedure to compute the symmetric difference A@?B. The output is also presented in the form of polygonal curves, where in particular the curves describing the union A@?B, the intersection A@?B, the difference A@?B, and the complement of the difference B@?A, are also obtained. This is related with the two equivalent formulas to compute the symmetric difference, namely A@?B=(A@?B)@?(A@?B)=(A@?B)@?(B@?A).