clear all;
x=-2:0.1:2;y=-2:0.1:2;y=y';
x1=ones(size(y))*x;
y1=y*ones(size(x));
z=x1.^2.*exp(-(x1.^2+y1.^2));
plot3(x1,y1,z,'r-');
grid on;hold on;
z1=0.05.*x1-0.05.*y1+0.1;
plot3(x1,y1,z1,'b-');
[m,n]=size(z);
for ii=1:m;
    for jj=1:n
    if z(ii,jj)==z1(ii,jj)
        plot3(x1(ii,jj),y1(ii,jj),z(ii,jj),'g-');
        ii,jj
    end
end
end