Good info from all thanks to explain how mine works here is a real example.
Abu dhabi-LHR night flight 10 hour duty,
24 hours off
LHR-AUH day flight arriving midnight 10 hour duty,
12 hours off
AUH- Paris (CDG) night flight 9 hour duty
12 hours off
CDG-AUH night flight 9 hour duty
12 hours off
AUH- Khartoum (KRT)- AUH night flight 10 hour duty
by the time you finish this, I would challenge anyone to say thaey are fit for an emergency or a CAT III approach!!