Final answer:
Snowball, a character in the novel 'Animal Farm' by George Orwell, originally came up with the idea to build a windmill.
Step-by-step explanation:
The idea to build a windmill originally came from the character Snowball in George Orwell's novel 'Animal Farm'. In this allegorical tale, Snowball, a pig, comes up with the idea as a way to improve efficiency and self-sufficiency on the farm. This is not a real historical event but part of a literary work, so the question likely pertains to an English or literature class discussing 'Animal Farm' and its characters.