C'mon Baby, Light My Fire. The ingredients needed to start a fire are traditionally illustrated in the fire triangle. The three legs of the triangle are fuel, oxygen and heat. When enough of these three factors is present, a chemical reaction occurs that results in fire. This is why you can start a fire with two sticks: The fuel is the sticks, the oxygen comes from the air and fiction provides the necessary heat. But this is far from the only circumstance in which friction starts a fire.