function BilinearQuadElementShowDistortion(X,Y,ME,NE,ND)
%    BilinearQuadElementShowDistortion的作用是畫(huà)出變形圖
plot(0,0);
hold on;
for I=1:NE
       for J=1:ND
        MEE=ME(J,I);
        x(J)=X(MEE);
        y(J)=Y(MEE);
        text(x(J),y(J),int2str(MEE));
    end
    x(ND+1)=x(1);
    y(ND+1)=y(1);
    plot(x,y,'b');
    s=0;
    t=0;
    for m=1:ND
       s=s+x(m);
       t=t+y(m);
   end
   dx=x(1)-x(2);
   dy=y(1)-y(3);
   xx=s/ND;
   yy=t/ND;
   text(xx+dx/6,yy-dy/8,['[',int2str(I),']']);
end