void xlat2d(double x[], double y[], int pts, double xoffset, double yoffset);
void scale2d(double x[], double y[], int pts, double xfact, double yfact);
void xlat2d(double x[], double y[], int pts, double xoffset, double yoffset);
void scale2d(double x[], double y[], int pts, double xfact, double yfact);