== start =====
start =>> Off_S1.prep   (*  :  *)
  Off_S1.true =>> Offx.leave   (*  | 2 : 2 *)
  Off_S1.true =>> S1x.set   (*  | 2 : 2 *)
== step =====
step =>> S1_Off.prep   (*  :  *)
  S1_Off.true =>> Offx.set   (*  | 8 : 8 *)
  S1_Off.true =>> S1x.leave   (*  | 8 : 8 *)
step =>> S1_S2.prep   (*  :  *)
  S1_S2.true =>> S1x.leave   (*  | 20 : 20 *)
  S1_S2.true =>> S2x.set   (*  | 20 : 20 *)
step =>> S2_Off.prep   (*  :  *)
  S2_Off.true =>> Offx.set   (*  | 80 : 80 *)
  S2_Off.true =>> S2x.leave   (*  | 80 : 80 *)
== upd =====
upd =>> Offx.upd   (*  :  *)
upd =>> S1x.upd   (*  :  *)
upd =>> S2x.upd   (*  :  *)
