parallelogramArea = (a, b, c) =>
  crossProduct(newVector(a, b), newVector(a, c))
Calculates the area of the parallelogram that can be
generated by the vectors ab and ac.

@param A point a, example: {x : 0,y : 0}
@param A point b, example: {x : 0,y : 0}
@param A point c, example: {x : 0,y : 0}
@return A vector ab, example: {x : 0,y : 0}
Note: Given that the area of the parallelogram is equal
to the length of the vector w = (ab)x(ac) times -1, if the
z coordinate of w is negative. With the right-hand rule
we can deduce that if the area is negative, then
the vector ab followed by the vector ac do not performs a
left-turn.