for k = 1:101
    x(k) = (k-1)*0.01;
    y(k) = (k-1)*0.01;
end
for k = 1:101
    for m = 1:101
        u(k,m) = sin(2*pi*x(m))*sin(2*pi*y(k))*exp(-(x(m)^2+y(k)^2));
    end
end
pcolor(x,y,u)
shading interp
hold on
for m = 1:9
    pm = m*0.1;
    nm = m*(-0.1);
    contour(x,y,u,pm,'k-')
    contour(x,y,u,nm,'k--')
end
hold off