In Orwell's novel "Animal Farm" one of the main themes is the manipulation of language to persuade and obtain means of power. This is the most important means by which the pigs begin to take advantage of the rest of animals in the farm. The pigs take on the leadership of Animal Farm since they are considered the most skilled in terms of intelligence than any other animal. By the play on words, they are able to fool everybody on the farm, promising them a better way of living without constraints or being forced to work, in other words they are 'granted' freedom.
The first way they do this is by the creation of the Seven Commandments in which they state that every animal is equal, that every four legged and winged animal is a friend and that no animal should do what humans do. However this changes little by little as the pigs distort the commandments and as the revolution takes shape. The animals are often played off with the word of 'equality', the pigs refer of it so everybody rejoices in the same rights but what they do is actually referring themselves as equal to humans in every possible way. They impose the rule that no animal should sleep on a bed or drink alcohol so no animal does, but when the pigs take over Mr. Jones' house, they do sleep in beds and they do drink beer. Also when they say that no animal should wear anything nobody does that either, yet later on they end up giving honor medallions which the awarded animals are allowed to wear Therefore the animals themselves are fooled with the pigs definition of equality which is more for the pigs own gain and comfort than for the well being of the animals.
The windmill symbolizes how the pigs abuse Boxer and the other animals that work on the farm, believing it is all for their own good. As for the barn, it is where they can manipulate the animals through the Seven Commandments that where written there. It symbolizes the vision of the pigs that cannot be broken because the others will accept it without complaint. As the pigs act for their own convenience, they know what triggers to pull in order to get the things the way they want. They prove themselves as being equals as humans and even better than them, causing oppression over others and over exploiting them so that they can create that perfect society where they are the only rulers.