pro show_slab
  L=20

  for i=0,100 do begin
     snr=string(i,form='(i03)')
     name="snap_"+snr
     
     readnew,name,h,"HEAD"
     readnew,name,x,"POS"
     readnew,name,u,"U"

     plot,x[0,*],u[*],psym=3,yr=[10,65],xst=1,yst=1,xtit='x',ytit='u',charthick=2,charsize=3

     save_screen,"frame_"+snr

  end
  stop
end