# convert to vector(x,y);

tovector(polar(x_,y_)):=vector(x*cos(y),x*sin(y));
tovector(point(x_,y_)):=vector(x,y);
tovector(x=x_,y=y_,z=z_):=vector(x,y,);
tovector(x=x_,y=y_):=vector(x,y);
tovector(x=x_ and y=y_):=vector(x,y);