Final answer:
The final sentence about robots washing windows likely aims to inform, surprise, or emphasize modernity, showcasing the author's intent to craft a rhetorically effective message that aligns with or challenges readers' expectations.
Step-by-step explanation:
In considering the final sentence of the provided passage, "The windows at the very top of the building are washed by robots!", we can infer the purpose of this sentence is likely to facilitate one of the following: to inform the reader about the use of technology in mundane tasks, to surprise the reader with an unexpected detail, or possibly to emphasize the modernity or advancement of the setting being described. Given the context of the text—with an emphasis on sentence construction and rhetorical effectiveness—it is probable that the purpose is to demonstrate a rhetorically effective way to convey the high-tech nature of the building or the modernization of tasks that were traditionally done by humans.
The discussion on periodic sentences, oratorical style, and the intended impact of a literary style on the reader indicates that the author of the original passage is concerned with the craft of writing, especially in how information is presented and how it affects the reader. Thus, the sentence about window-washing robots might serve to conclude a point or to introduce a concept that challenges the reader's conventional expectations regarding technology's role in our daily lives.