How about this one. Given a green sapling, 1.5 inches in diameter, 5 ft long, your sharp rock and a fire... how do you make a hasty, field expedient spear out of it that will bring down a feral pig?
Assume we will give it to a brawny young man that isn't too bright and will poke a feral pig with a spear and maybe live through it.
/johnny
At the end of the green sapling, I'd cut a small space, really a small split, to fit the arrowhead type cutting edge. Then, I'd take green vine and wrap the edge in there and get pine sap and melt it in the fire and slather that around the vine everywhere so it would shrink and get hard so the arrowhead would be solid in there. After it was cool so it would be hardened, give it to the stupid kid you mentioned to stick it in a feral pig. Then, you would cook it.
Use rock to sharpen spear, fire harden the pointy end of the wood, fine tune it with the rock. Repeat as necessary to get a decent point.