What is the author's style in Sweeney Todd: The Demon Barber of Fleet Street by Hugh Wheeler?

As the plot unfolds, Wheeler often creates a collage of scenes, making quick cuts back and forth between story lines. This juxtaposition emphasizes the thematic unity in the play. One such segment involves Sweeney and Anthony. As the scene cuts back and forth between the two characters, the play's focus on the interplay of innocence and corruption is reinforced. The scene opens with Anthony searching the streets of London for Johanna, singing of her beauty and insisting that he will save her. While he continues the search in one corner of the stage, the barber shop is lit in another, where Sweeney also praises Johanna's beauty. He doubts though that he will see her again. The two men sing her name together as Sweeney vents his rage by slitting a customer's throat. An ironic touch is added when the customer's mouth opens simultaneously with theirs as his throat is cut.