program square
      real x(5),y(5)

      idummy=pgopen('/xwin')
      call pgenv(-10.0,10.0,-10.0,10.0,1,0)

      x(1)=2
      y(1)=2
      x(2)=2
      y(2)=-2
      x(3)=-2
      y(3)=-2
      x(4)=-2
      y(4)=2
      x(5)=x(1)
      y(5)=y(1)

      call pgline(5,x,y)

      call pgclos
      end