program square_rot
      real x(5),y(5),xnew(5),ynew(5)
      write(*,*)'drgrees for rotation?'
      read(*,*)n
      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)

      d_theta=2*3.14159/360
      theta=n*d_theta
     
      do i=1,5 
        xnew(i)=x(i)*cos(theta)-y(i)*sin(theta)
        ynew(i)=x(i)*sin(theta)+y(i)*cos(theta)
      end do

      call pgline(5,xnew,ynew)

      call pgclos
      end