I feel like the evolution of weaponry was something like:

1. hit it with a stick
2. throw a rock at it
   3a. hit them with a rock on the end of a stick
   3b. use a string / spring to throw the rock faster / harder
3. hit it with a SHARP rock on a stick
4. throw the sharp rock on a stick AT them
5. use a string / spring to throw the sharp rock on a stick faster / harder
6. use a lever to pull the string back harder to throw the sharp rock on a stick even harder / faster
7. put the rock in a tube on top of some explosives then point the end of the tube at someody.
8. put some tracks on the inside of the tube to spin the rock so it flies straighter
9. hollow out the rock, and put more explosives inside of it etc etc etc