Ships (Visual Imagery)
Throughout the course of Purgatorio, Dante and his narrative journey are often described using the imagery of a voyage on a ship. This has particular import as metaphors of navigation are dominant in the Commedia, and the use of specifically marine imagery is taken up in the Purgatorio and redeployed throughout the remainder of the poem to give a sense of the harsh journey ahead, while calling back to the epic sea voyages of Aeneas or Odysseus.
The "P"s on Dante's Forehead (Visual and Tactile Imagery)
Dante enters the seven terraces with seven "P"s on his forehead, and one is removed each time he advances up a terrace. These "P"s represent sins (peccatum being Italian for sin); the imagery of blemishes being removed from Dante's forehead mirrors the removal of sins through Christ's atonement, making sinners "white as snow" (Isaiah 1:18). Similarly, marks on the forehead were symbols of sin in Revelation 13:16.
The Souls in Penance (Visual and Auditory Imagery)
As Dante reveals the punishments suffered by the souls in penitence, he uses specific and effective imagery to respond to what sins they have committed in life. The prideful, for example, are presented as horribly compressed and forced to bear heavy burdens; they seem like ugly statues. Yet other sinners, like the envious, have their eyes shut, and as such, Dante shifts to use more auditory imagery. In sum, Dante appeals to the reader's different senses as he explores different modes of punishment.
The Color Green (Visual Imagery)
Although the Inferno asks that those who enter it "Abandon all hope," Purgatorio sees Dante develop the theme of hope through the imagery of the color green. As early as the third canto, Dante mentions that hope ensures "eternal love" if it "maintains a thread of green," and throughout the Purgatorio, plants and green clothing come to symbolize renewal. Indeed, the Garden of Eden is a sort of green Paradise, full of plants.
