What are the expressions that reflect the poet's sense of futility in the poem "Last Lesson of the Afternoon"?

"Last Lesson of the Afternoon" by poet D.H. Lawrence quite holistically reflects the poet's sense of futility in that it showcases the complaints of a teacher who feels that his work is no longer productive or significant to his poorly behaved and disinterested students. 

We can see this futility specifically in the language chosen in this poem. For example, Lawrence uses the metaphor of a "pack of unruly hounds" to represent the students who "hate to hunt" (in other words, who have no desire to learn the lessons the teacher is offering up to them), which seems to exaggerate the students' behaviors to the reader. These students are not just children, but beasts--and uncontrollable ones at that! This same hyperbolic language can be detected in the second stanza when Lawrence refers to the written work of the teacher's pupils as the "insults of blotted pages." The teacher is not only recognizing that his students are failing in their coursework, but taking this fact as a personal blow and characterizing it as something done intentionally to cause him harm. 

Throughout the poem, Lawrence also uses a series of rhetorical questions to indicate the futility of the teacher's work. The teacher asks, "What is the point of this teaching of mine, and of this / Learning of theirs?" and "Why should we beat our heads against the wall / Of each other?" It is clear that the teacher already knows the answers to these questions; in his opinion at least, there is no point in any of it!