% .............................................................     
    function [shape,naturalDerivatives]=shapeFunctionL2(xi)

    % shape function and derivatives for L2 elements
    % shape : Shape functions
    % naturalDerivatives: derivatives w.r.t. xi 
    % xi: natural coordinates (-1 ... +1)
   
    shape=([1-xi,1+xi]/2);
    
    naturalDerivatives=[-1,1]/2;
             
    end % end function shapeFunctionL2
  
