functor
import
   Browser(browse:Browse)
define
   proc {Ping N}
      if N==0 then {Browse 'ping terminated'}
      else {Delay 500} {Browse ping} {Ping N-1} end
   end
   proc {Pong N}
      {For 1 N 1
         proc {$ I} {Delay 600} {Browse pong} end }
      {Browse 'pong terminated'}
   end
in
   {Browse 'game started'}
   thread {Ping 50} end
   thread {Pong 50} end
end