Read the following excerpt from Robert Louis Stevenson's Essay in the Art of Writing and answer the question: There is nothing more disenchanting to man than to be shown the springs and mechanism of any art. All our arts and occupations lie wholly on the surface; it is on the surface that we perceive their beauty, fitness, and significance; and to pry below is to be appalled by their emptiness and shocked by the coarseness of the strings and pulleys. In a similar way, psychology itself, when pushed to any nicety, discovers an abhorrent baldness, but rather from the fault of our analysis than from any poverty native to the mind. And perhaps in aesthetics the reason is the same: those disclosures which seem fatal to the dignity of art seem so perhaps only in the proportion of our ignorance; and those conscious and unconscious artifices which it seems unworthy of the serious artist to employ were yet, if we had the power to trace them to their springs, indications of a delicacy of the sense finer than we conceive, and hints of ancient harmonies in nature. […] I must therefore warn that well-known character, the general reader, that I am here embarked upon a most distasteful business: taking down the picture from the wall and looking on the back; and, like the inquiring child, pulling the musical cart to pieces.

Re-read the line in bold. What example of figurative language is this?

Simile
Metaphor
Hyperbole
Onomatopoeia