In terms of external factors that play a role in the development of Napoleon's character, the rivalry with Snowball for leadership on the farm is something that drives him. Once Jones is overthrown and the pigs are given the title of leaders on the farm, the antagonism between Snowball and Napoleon reaches a fevered pitch. Both of them hold fundamentally different viewpoints on the direction of the farm and the power struggle between them becomes increasingly apparent. This is shown brilliantly in the construction and schematics of the windmill. As Snowball struggles day and night to design the windmill, filled with architectural details and books abundant, Napoleon, who has been completely against the windmill, enters one evening and studies the designs. He then urinates on them to show his disgust. When the speeches in favor and against the windmill present themselves to the animals, Napoleon's speech consists of a high pitched whistle in which his pups turned attack dogs chase Snowball off the farm for good, enabling him to hold complete and unlimited power over the farm. This rivalry with Snowball helped to harden Napoleon, making him more brutal, more intense, and more driven to hold and consolidate power over both his fellow animals as well as other farms around Animal Farm. The factor of competition with Snowball and then ensuring that victory over him was a permanent state of being is a very intense motivating factor for Napoleon and his development in the novel.