ellipse(x,cf,ps,xnorm,nsects)
float x,xnorm,cf[4][10],ps[4][10];
int nsects;
{
	int m;
	float op;

	for(m=0; m<nsects; m++) {
		op = x + cf[1][m] * ps[1][m] + cf[3][m] * ps[2][m]
		     - cf[2][m] * ps[3][m] - cf[4][m] * ps[4][m];
		ps[2][m] = ps[1][m];
		ps[1][m] = x;
		ps[4][m] = ps[3][m];
		ps[3][m] = op;
		x = op;
		}
	return(x * xnorm);
}