"Right now,now, at this very moment, an old black ram is having sex with your white ewe."
Act 1; Scene 1
Act 2; Scene 3
"Tell her everything. Ask her to help restore you to your rank...Ask her to heal this rift between you and your husband, and I'd take any bet that your relationship with Othello will be restored to greater strength than it had before."
Act 3; Scene 3
"I will lose this handkerchief in Cassio's lodging and let him find it. Little things as light as air, to the jealous, are proofs as strong as words of scripture. The Moor already is feeling the effects of my 'Poison'"
In this act, Iago is with Cassio informing Barbantio that Desdemona has married Othello. Iago's development has altered the theme and will later on develop the plot. Ever since Cassio became lieutenant, Iago has changed and developed which is causing him to go behind Othello's back.
Act 4; Scene 1
"'Keep on working, my 'medicine', keep on! This is how gullible fools are tricked, and many good and faithful wives, although innocent, are accused."
In this act, Iago is explaining to Cassio that since he got fired, he can go on and ask Desdemona to beg Othello to give Cassio his job back as lieutenant. This is showing Iago's intelligence developing through the acts so far. Without the development of Iago's intelligence, the plot of th novel wouldn't exist.
Act 5; Scene 1
"'Now, wheather he kills Cassio or Cassio kills him, I come out ahead. If Roderigo lives, he's going to demand that I repay him for the heaps of gold and jewels I've tricked him into giving me as gifts for Desdemona.'"
In this act, Iago is in Cassio's room getting ready to plant Desdemona's handkerchief to prove that she is having an affair. Iago's intelligence has developed once again which is what is creating the plot of this play. The development of this character is what allows the novel to advance the plot along with the theme.
Act 5; Scene 2
"It's shameful, but Iago knows that Desdemona and Cassio have committed adultery with one another a thousand times."
In this act, Iago just finished speaking to Othello about Desdemona and Cassio's 'affair'. When they finished, Othello wasn't listening to Iago talking to himself. Iago is stating that his plan is working to kill innocent people and destroy Othello. Iago is growing as a character and planning the deaths of many people.
In this act, Iago is explaining his plan to kill Iago and Rodrigo. He has a plan for every circumstance than can happen. His development throughout this play is shown through all of a Iago's plans and ideas to kill innocent people and destroy Othello.
In this act, Othello, Desdemona and Emilia all end up dying because of Iago's actions throughout the entire play. Iago's development led to deaths of these characters along with the development of the plot. Cassio never died which now puts him in Othello's spot. Iago wanted to take Cassio's role as lieutenant but now not only does he not have that, Cassio is now in charge.