Once my dog ate all the Scrabble tiles...
He kept leaving little messages around the house.
One Sunday a pastor found several letters awaiting him. He opened one and found it contained the single word, "Fool."
Quietly and with becoming seriousness he shared the letter with the congregation and announced, "I have known many an instance of a person writing a letter and forgetting to sign his name, but this is the only instance I have ever known of someone signing his name and forgetting to write the letter."
Compare a complex sentence to a cat...
Cats have claws at end of paws.
Complex sentence has a pause at the end of a clause.