> Phi[1]:=(xi,eta)->5/4*(1-xi^2)*(1-eta^2);

                                             2          2
           Phi[1] := (xi, eta) -> 5/4 (1 - xi ) (1 - eta )

> plot3d(Phi[1],-1..1,-1..1,grid=[20,20],axes=boxed,
> scaling=constrained, style =patch, shading=none);

> 
