The scene where Dante is chased by the dog and encounters Virgil. The thin wire lead which is being used to control the dog is visible at the left of the scene.
When Francesca and Paolo fly down to speak to Dante in the Circle of Lust, the Kirby wires supporting them are visible.
The penultimate scene: as Virgil leads Dante through the subterranean passage, he suffers an uncharacteristic moment of clumsiness (he trips, stumbles, and has to pull his own toga out from under his foot).