Don't Repeat Yourself (or the Hive Collapses)

Placeholder prose. Every cell in the comb is the same shape because the rule for a cell lives in one place. The opening section sets up the analogy and states the principle in one sentence.

Second paragraph of placeholder body copy. It names the specific bug duplication produces and why it is always found late.

The same rule, written twice

Placeholder lead-in to the code sample below.

// api/intake.ts
if (load > 40) reject("too heavy");

// worker/intake.ts
if (load > 45) reject("too heavy"); // nobody updated this one

Two copies of a rule means one of them is already out of date and you do not know which.

One rule, one home

Closing placeholder paragraph. It restates the rule, concedes that a little duplication beats the wrong abstraction, and hands off to the next article.