How does Augustine of Hippo use imagery in Confessions?

Imagery:

"Where was I, and how far was I banished from the delights of your house in that sixteenth year of my flesh when the madness of lust (forbidden by your laws but too much countenanced by human shamelessness) held complete sway over me and to this madness I surrendered myself entirely!" Book II, Chap. 2

"And so I muddled over the clear spring of friendship with the dirt of physical desire and clouded over its brightness with the dark hell of lust." Book III, Chap. 1

"But if this fig were to be eaten by some Manichean saint (always assuming that the picking of it was someone else's and not his guilt), it would be digested and then at the end of the process this saint would breathe out from the fig, angels, or rather actual particles of God, at every groan or sigh in his prayer, and these particles of the most high and true God would have remained bound up in the fruit if they had not been set free in this way by the mastication and digestion of some sainted 'elect'." Book III, Chap. 10