The professor wanted to explain solipsism in eight lines. (solipsism: in this context radical subjectivism, certainty of one's own mind alone) If only one's own mind was certain, how could a writer be sure of a reader? Her cerebral puzzle left the student editor cold. (cerebral: intellectual, analytical, thoughtful) He could admit the question yet decline eight lines of pedantry before the football results. (pedantry: nitpicking, overscrupulous detail, showy erudition)
A long heel mark across his desk gave her an idea. Its owner was absent; its existence was patent. (patent: obvious, evident, manifest) Her first draft was still pedantic, the second almost empty. (pedantic: fussy, nitpicking, hairsplitting) Then she used the heel mark to ask what its presence could prove and what one's mind had to supply.
The editor printed the third draft. On Monday a boot repairer answered with a sketch of the heel. The teacher's introspection had led to an unexpected correspondence about the world outside her office. (introspection: self-examination, reflection, inward contemplation)