> with(plots):
> a:=plot3d(x^2-y^2,x=-3..3,y=-3..3,style=patchcontour,shading=z):a;
> b:=implicitplot3d(y-x-1,x=-3..3,y=-3..3,z=-3..3,title=`plane`,color=green):b;
> solve({z=x^2-y^2,y=x+1,x=t},{x,y,z});
> c:=spacecurve(vector([t, t+1, -2*t-1]),t=-3..3,color=black,thickness=2):c;
> display(a,b,c);
>