         E("stable-sub-rules").innerHTML = ""
         if rule[0] isnt 0
           @ruleset = Rules.stabilize_vacuum rule
+          try
+            @inverse_ruleset = (Rules.reverse r for r in @ruleset)
+          catch e
+            @inverse_ruleset = null
           E("stablize-rule").checked = false
           E("rule-stabilization-pane").style.visibility = "visible"
           @show_rule_stabilization()

          @update_time()
          @recordFrame()

      recordFrame: ->
        return unless @encoder?
        @encoder.addFrame @canvas.getContext("2d")

            window.clearInterval @field_player
            @field_player = window.setInterval(@field_player_proc, @step_delay)

      update_time: ->
          @time_display.innerHTML = "" + @generation  if @time_display

