`triangle-vertices-edges`procedureReturns a pair of two vectors containing the vertices and edges of the given triangle, respectively. If the edge argument is not NULL, then it is identical to the first elements of the edges vector.

`triangle-vertices-edges`procedureReturns a pair of two vectors containing the vertices and edges of the given triangle, respectively. If the edge argument is not NULL, then it is identical to the first elements of the edges vector.