The windmill takes center stage after the revolution. Initially it is Snowball's idea to make a windmill for power, but after a while Napoleon makes it his own project. Moreover, he accuses Snowball of destroying and sabotaging the project.
Here is what Napoleon says:
‘Comrades,’ he said quietly, ‘do you know who is responsible for this? Do you know the enemy who has come in the night and overthrown our windmill? SNOWBALL!’ he suddenly roared in a voice of thunder. ‘Snowball has done this thing! In sheer malignity, thinking to set back our plans and avenge himself for his ignominious expulsion, this traitor has crept here under cover of night and destroyed our work of nearly a year. Comrades, here and now I pronounce the death sentence upon Snowball. ’Animal Hero, Second Class,’ and half a bushel of apples to any animal who brings him to justice. A full bushel to anyone who captures him alive!’
In time the windmill is finished, but later it is destroyed again when the humans attack. The animals win again and they call the battle the Battle of Windmill.
‘But they have destroyed the windmill. And we had worked on it for two years!’
‘What matter? We will build another windmill. We will build six windmills if we feel like it. You do not appreciate, comrade, the mighty thing that we have done. The enemy was in occupation of this very ground that we stand upon. And now — thanks to the leadership of Comrade Napoleon — we have won every inch of it back again!’
The windmill is a rallying cry for Napoleon, and he galvanizes people to his cause through the project. Finally, the windmill is not used to create power, as Napoleon said, but to mill corn for profit for the pigs. In the end, the windmill is a subtle use of power to control the animals.