This method takes three arguments: a list of existing points, a new point and a tolerance. It returns true if the new point is functionally identical to one of the existing points and returns false if the new point is not functionally identifical to any of the existing points. It loops through the list of existing points and compares each point in the list with the new point argument. If the absolute value of the difference between the X value of the existing point and the X value of the new point is less than the tolerance OR the absolute value of the difference between the Y value of the existing point and the Y value of the new point is less than the tolerance, THEN the new point is functionally identical to the existing point, and the function returns true. If the function reaches the end of the list without returning true, it returns false.