What are 3 different ways Shylock demonstrates revenge?

Shylock, one of the characters in Shakespeare's play The Merchant of Venice, is vengeful almost by definition. He is a moneylender, so he has complex and sometimes tense relationships with the people who borrow from him. Moreover, he is Jewish, and thus he often feels slighted by certain Christians he comes into contact with. Let's go over three different ways that Shylock demonstrates revenge in the course of the play.

1. This is a big one: he demands a pound of Antonio's flesh as payment for a debt.

Antonio, one of the most important merchants in Venice, is one of the Christians with whom Shylock has conflict. The moneylender feels he is treated poorly by Antonio, and he seeks revenge on him. Here, Salarino asks Shylock why he would want a pound of flesh (instead of money):

SALARINO

Why, I am sure, if he forfeit, thou wilt not take
his flesh: what's that good for?

SHYLOCK

To bait fish withal: if it will feed nothing else,
it will feed my revenge. He hath disgraced me, and
hindered me half a million; laughed at my losses,
mocked at my gains, scorned my nation, thwarted my
bargains, cooled my friends, heated mine
enemies; and what's his reason?

This is an excerpt from a longer speech that Shylock makes about the nature of revenge:

If a Jew wrong a Christian, what is his humility? Revenge. If a Christian wrong a Jew, what should his sufferance be by Christian example? Why, revenge. The villainy you teach me I will execute—and it shall go hard but I will better the instruction.

2. Shylock refuses Bassanio's attempt to pay off Antonio's debt, even though Bassanio offers Shylock much more than the amount of the original loan. (What would Shylock actually do with a pound of anyone's flesh? He is acting out of hatred, not logic. He could just take the generous offer of money, but he will not.)

3. Shylock shows no mercy to Antonio, even when Antonio begs for it, and even when Portia (disguised as a legal expert) pleads with him to spare Antonio's life. Portia asks him to show mercy, but Shylock stands his ground, stating in a court trial that he demands a pound of flesh and will not accept another form of payment. 

ANTONIO
I pray thee, hear me speak.

SHYLOCK
I’ll have my bond. I will not hear thee speak.
I’ll have my bond, and therefore speak no more.
I’ll not be made a soft and dull-eyed fool
To shake the head, relent and sigh, and yield
To Christian intercessors. Follow not.
I’ll have no speaking. I will have my bond.