How does Napoleon show his disapproval of Snowball's plan to build the windmill in Animal Farm?

In Ch.5 we read how Snowball with a lot of painstaking
effort worked out the details of the plan for his
windmill:

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Snowball used as his study a shed which had once
been used for incubators and had a smooth wooden floor, suitable for drawing on. He was
closeted there for hours at a time. With his books held open by a stone, and with a
piece of chalk gripped between the knuckles of his trotter, he would move rapidly to and
fro, drawing in line after line and uttering little whimpers of excitement. Gradually
the plans grew into a complicated mass of cranks and cog-wheels, covering more than half
the floor,which the other animals found completely unintelligible but very
impressive.

However, Napoleon
who was jealous of Snowball and whom he had always considered to be a threat to his
position disapproved of Snowball's plan to build the
windmill:

Only
Napoleon held aloof. He had declared himself against the windmill from the
start.

He expressed his
disapproval in an obnoxious manner by urinating over Snowball's intricately drawn out
plans for the windmill:

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One day, however, he [Snowball] arrived
unexpectedly to examine the plans. He walked heavily round the shed, looked closely at
every detail of the plans and snuffed at them once or twice, then stood for a little
while contemplating them out of the corner of his eye; then
suddenly he lifted his leg, urinated over the plans, and walked out without uttering a
word.