Napoleon pees on them. At this time, Napoleon acts like he has no respect for Snowball. but in reality, Napoleon is going to take those windmill plans. The animals are going to have to build the windmill, and Napoleon is going to take the credit for the plans. The animals are going to have to work longer hours with less food than ever before, but will do so with the spirit of "Animalism". Squealer's propaganda will continue to paint a pretty picture of life with the windmill, as the animals move ever closer to believing that Snowball is, in fact, an enemy spy.
I'll bet some teachers wait a lifetime for a crack at this question...
To show his opinion of Snowball's drawings for the windmill, which he opposes, Napoleon pees on the papers. Of course, after driving Snowball off the farm, Napoleon goes ahead and builds the windmill, claiming it was his idea in the first place. Later, when a storm destroys the windmill because it is poorly designed, Napoleon then convinces the other animals that Snowball came back in the dead of night and sabotaged the construction.