It is said Squealer would turn black into white; how is this shown in Animal Farm?

In the
opening of ,is described as the best known of the male pigs (aside fromand Snowball). He could
"turn black into white" because he was a very persuasive talker. 

He was a brilliant talker, and when he was arguing some difficult
point he had a way of skipping from side to side and whisking his tail which was somehow very
persuasive. 

Notice that asis being hailed for his
persuasive speech, it is his "skipping from side to side and whisking his tail" that
made him persuasive. This indicates that he was good at distracting those he spoke to and he was
very good at changing his positions (going from side to side) in order to win arguments or in
order to justify his new positions. 

There are many times in the novel when
the commandments are changed and Squealer is able to fool the animals that the commandments have
not been changed. Therefore, he is able to change his position (from black to white) without the
animals even knowing it. At the end of , the pigs start sleeping in beds. This contradicts the
initial fourth commandment which stated that "No animal shall sleep in a bed." When
Clover suspects something, Muriel spells out the commandment which had been updated to state
that "No animal shall sleep in a bed with sheets." Squealer
assures them that the commandment was always stated in this way: to only outlaw beds with
sheets. 

You did not suppose, surely, that there was ever
a ruling against beds? A bed merely means a place to sleep in. A pile of straw in a stall is a
bed, properly regarded. The rule was against sheets, which are a human invention.