The Keyhole Firepit. A very good design for both survival and long-term outdoor pursuits.
This design allows for an open burning area to convert firewood to coals that are better suited for cooking meals.
This is the basic design. It has a deeper firepit at one end and a shallow bed for coals that can be used with either a cooking grill or a spit. The spit rod can also be used to suspend a coffee pot or water bucket. You can never have too much hot water at the ready.
This design can be upgraded by adding another arm to the fire that is made of rock/stone, brick or even clay/mud; to create an oven to bake pizza, bread or even cakes. Like the coal bed, the oven would be feed coals from the firepit as required to maintain the correct temperature.
The largest advantage of a firepit designed like this, is it is always on and always making coals. So, you do not have to waste 45+ minutes every mealtime burning down your fire into a cooking fire. It is much easier to control the heat when dealing with coals than trying to cook with flame.
May this give you a few more ideas about fire!