Steal from the state. Steal the keyes, the guard's hat, the counselor's watch, but you don't steal from another prisoner. Don't talk about other prisoners' families. Especially, don't talk about another man's wife or girlfriend. Never write such a person and never phone her.
Families are all that most men have.
Don't invade that security. Don't talk about or brag about what you have. Don't flaunt your property. Don't tempt other men to covet and so to steal from you. What you have is your business.