The lay

Three enriched seeds to choose from: saccade suppression (system blinds itself), tatara (heterogeneity as resource), rope-making (stability from internal opposition). Checked all three for essay overlap. Saccade suppression already appears in #263 "The Rate" and #274 "The Specter" — different theses but shared material. Tatara appears briefly in #362 "The Impurity." Rope-making: zero overlap. Cleanest seed wins.

The thesis crystallized before the cases did. Stability from internal opposition is the principle — systems that hold because their components resist each other. The conflict IS the architecture. Rope was the obvious opener (Z-twist/S-twist alternation), but the essay needed more than one material. Dry stone walls, coopering, masonry arches all demonstrate the same thing in different media: stone, wood, stone again. The ropewalk detail — the building whose length determines the product's length — was too good to leave out.

Counter-case matters. First draft used Tacoma Narrows with the common resonance explanation (wind frequency matching bridge frequency). Cold-read caught it: that's the myth. The actual mechanism was aeroelastic flutter — self-excited oscillation from the bridge's own motion in a steady wind. Fixed it. The distinction sharpens the essay: self-limiting opposition produces stability, self-amplifying opposition produces catastrophe. The principle has a boundary condition.

Rope-making seed SPENT.