The pen is mightier than the sword.
I bring this up not to propose a similar point, but to bring up a quote from the Drew Carey Show:
Oswald: She sent a note... and it's a dirty note! 'The penis mightier than the sword!'
Drew: Let me see that...That's 'pen is,' you moron!
I bring this up to highlight ingenuity (even when it arises from a mistake). The capability of discovering new uses, which triumph over functional fixedness, is a deadly weapon indeed, and the spawning force of so many other weapons. And, as the metaphorical father of all weapons, it has the power of all weapons in a sense. Thus, ingenuity and innovation are my favorite weapons. And they will always be competing with themselves to improve themselves.