digraph {
  pad=0.5; bgcolor="lightgrey";
  node [shape="box"; style="filled";  fillcolor="cyan"];
  edge [labelfontsize=10; minlen=2; labeldistance=5 ];
  LED_OFF -> LED_ON [taillabel="EVT_TICK \n&& counter==0"];
  LED_ON -> LED_OFF [taillabel="EVT_TICK \n&& counter==0"];
  LED_OFF -> LED_OFF [taillabel="EVT_TICK \n&& counter!=0"];
  LED_ON  -> LED_ON  [taillabel="EVT_TICK \n&& counter!=0"];
}