x = -10:1:10;
y = -10:1:10;
z = zeros(21, 21)
for xx = x
    for yy = y
        z[xx+11, yy+11] = 100 - xx^2 - yy^2
    end
end
figure()
s = pcolor(x, y, z)
s.set_edgecolor("flat")
colorbar(gca(), s)
colormap(s, "jet")
xlabel("X");
ylabel("Y");