Sergeant "BLOGGINS!"
Bloggins "Yes Sarge!"
Sergeant "They're coming! Get out there and stand guard at Checkpoint Charlie."
Bloggins "Yes Sarge!"
Sergeant "What's today's challenge phrase?"
Bloggins "Lefty loosey, Sarge!"
Sergeant "What's the response?"
Bloggins "Righty tighty, Sarge!"
Sergeant "Good. Now get out there and guard the crossroad. Don't even think of abandoning your post until properly relieved!"
Bloggins "Yes Sarge!"
So off trotted Pte Bloggins to man his checkpoint. Fast forward a while - quite a while in fact - and poor Bloggins is still at his post waiting to challenge anyone who comes near.