Four Marks — How do you survive lost in the wild, and what kills you first?

What should you actually do first if you are lost in the wild with nothing? Warmth, then water, then food — because cold can kill in hours, thirst in days, and hunger takes weeks. In this lesson daylight is a bag of hours that runs out, and you get three days to spend it: build a shelter small enough to hold your own heat, pull air through a fire, boil water that already looks perfectly clean, and find north from a stick and its shadow. Somebody woke up on this hillside before you and left four charcoal marks on the rock, with a drawing beside each one. Find out what they spent their last day on.