Here was a recipe neither cousin could comprehend. (comprehend: understand, grasp, apprehend) Two tablespoons of an obscure substance were followed by something illegible. (obscure: little-known, unfamiliar, little-understood) It might have said "patience." The ambiguity grew worse with every line. (ambiguity: equivocalness, equivocality, double meaning) One cousin proposed an analogy with another dish. (analogy: comparison, parallel, likeness) The other pointed out that the analogy would make the yellow soup almost entirely mustard.
They tried to deduce the meaning from the handwriting. (deduce: infer, conclude, derive) A penciled loop could allude to a missing ingredient or indicate that the reader should stir. (allude: hint, suggest, intimate) They found the same mark in instructions to fold a napkin. That discovery seemed to contradict both ideas. (contradict: deny, dispute, controvert) The crucial distinction was between the ink and the pencil. (crucial: critical, pivotal, essential; distinction: difference, differentiation, contrast) Grandmother had written the recipes in ink. Somebody else had checked them in pencil.
Grandfather arrived with an empty dish. He was mildly amused by their perplexity. He had marked the things he liked: a loop for a little more, two loops for a lot. The word after the two tablespoons was certainly "patience." Grandmother had put it there to disconcert him. (disconcert: unsettle, discompose, discomfit) Its purpose, he admitted as the soup came to the table, had been effectual. (effectual: effective, efficacious, successful)