This video shows how to make a fire using only sticks found in nature and a string.  [Note: As this video shows, starting a fire using the “spindle-drill” method is rather specific, where it is useful for an additional notch to exist at the point of contact with the stick in order for it to gather a smoldering lump of dust that is created by the friction.  Previously I was under the impression that it was simply heat from the friction that directly caused the combustion, not realizing that such a notch is useful to accumulate a burning coal.  I’ve seen it done without using a string and bow as well, but I’m sure the bow makes the process much easier.]