Try using relay triggers, have a trigger_once target two trigger_relays, one to turn on the light and one to trigger two more trigger_relays, one to turn off the light and yet another trigger_relay, have that second one trigger either the first pair or continue to trigger two more,
Trigger once
|
Trigger_Relay01 - Trigger_Relay01 (Light on)
| (wait time)
Trigger_Relay02 - Trigger_Relay02 (Light off)
| (wait time)
Trigger_Relay01 - Trigger_Relay01 (Light on)
Since you can set lights to on and off with the trigger_relays you can just use them as a more complicated Multi_Trigger