[x,y,z] = ellipsoid(1,2,3,2,2,5);	% elipsoid
  % èást elipsoidu:
x = x(1:10,1:10);y = y(1:10,1:10);z = z(1:10,1:10);
[U,V,W] = surfnorm(x,y,z);			% normály
quiver3(x,y,z,U,V,W,2,'k');hold on
surf(x,y,z);











