matlab中三维制图程序错哪里了

matlab中三维制图程序错哪里了
all;
t=-2:0.1:2;
[x,y]=meshgrid(t,t);
z=-(x.^2+y.^2)+250;
surf(x,y,z)
xlabel('x');ylabel('y');zlabel('z');
hold on;
t1=-2:0.001:2;
h=plot3(t1,zeros(1,length(t1)),-t1.^2+250,'LineWidth',3);
legend(h,'要旋转的曲线');
set(gcf,'Units','Normalized','Position',[0,0,1,1]);