X=-2:0.1:2; 
Y=X;
[x,y]=meshgrid(X,Y);

z=x.^4-2*x.^2+y.^4-2*y.^2+1;

surf(x,y,z)

%alles grafikes parastaseis
contour(x,y,z)

surfc(x,y,z)

pcolor(x,y,z)