A skeleton LSD account for a travelling by bus scenario ...

agent route {
	oracle bus_number, origin, terminus
	derivate stops is list_of_locations(bus_number, origin, terminus)
}

agent bus {
	state bus_location, onstop
	derivate atstop

	state livery
	state bus_number
	state destination
	state origin

	state bell_has_been_rung
	state bus_stopping = bell_has_been_rung
}

agent ticketmachine {
	state fare_offered

}

agent ticket(ID) {
	state ID
}

agent driver {
	state next_stop
	oracle bus_destination
	protocol
		bus_stoppping --> bus_location = nextstop; onsstop = true
		fare_offered > fare_required --> ID++; ticket(ID)

}

agent passenger {

	state passenger_location, passenger_destination

	role joiningBus {
		oracle bus_destination, bus_location
	}
	
	role onBus {
		oracle bus_location
		derivate passenger_location is bus_location
	}

	role leavingBus {
		oracle bus_location
		protocol
			pa
			passenger_destination == bus_destination --> passenger_location = bus_location
}