Animal Farm by George Orwell?

Question

What does the windmill represent to all the animals working on it and to Napoleon.

Answer 1

Here's an explanation of what the windmill meant from Sparknotes:

"The great windmill symbolizes the pigs’ manipulation of the other animals for their own gain. Despite the immediacy of the need for food and warmth, the pigs exploit Boxer and the other common animals by making them undertake backbreaking labor to build the windmill, which will ultimately earn the pigs more money and thus increase their power. The pigs’ declaration that Snowball is responsible for the windmill’s first collapse constitutes psychological manipulation, as it prevents the common animals from doubting the pigs’ abilities and unites them against a supposed enemy. The ultimate conversion of the windmill to commercial use is one more sign of the pigs’ betrayal of their fellow animals. From an allegorical point of view, the windmill represents the enormous modernization projects undertaken in Soviet Russia after the Russian Revolution."

And here is more relevant information from CliffsNotes:

"Snowball’s plans for the windmill and programs reflect Trotsky’s intellectual character and ideas about the best ways to transform Marx’s theories into practice."

The destruction of the windmill marks the failure of Snowball’s vision of the future. It also allows Orwell to again demonstrate Napoleon’s incredible ability to seize an opportunity for his own purposes. Afraid of seeming indecisive and a failure while all the animals stare at the toppled windmill, Napoleon invokes the name of Snowball as Squealer does with Jones: “Do you know,” he asks, “the enemy who has come in the night and overthrown our windmill? SNOWBALL!” For the remainder of the novel, Snowball will be used as a scapegoat for all of Napoleon’s failings; his commands to begin rebuilding the windmill and shouting of slogans occur because he does not want to give the animals any time in which to consider the plausibility of his story about Snowball. Although he shouts, “Long live Animal Farm,” he means, “Long live Napoleon!”

The effect of Napoleon’s propaganda (that all the work the animals are doing are for their own benefit and not of the theiving humans) is also seen in Boxer’s unflagging devotion to the windmill. Even when warned by Clover about exerting himself, Boxer can only think, “I will work harder” and “Napoleon is always right.”

Answer 2

The Battle of the Windmill in Animal Farm is taken from the Battle of the Windmill that happened in Canada

http://en.wikipedia.org/wiki/Battle_of_the_Windmill

Answer 3

That life is continuous circle and that no matter how hard we try to change and better society it always will be tainted and cruel.