plot (0,0) · mutate · gen 1 · fitness 0.722
Iso-contour tracing of a dual-subharmonic Stuart vortex sheet undergoing pairing, roll-up, and rib-braid instability. 剪切层涡旋配对与等值线流动。
Where the northern dry front shears against the dense trench, the ash separates into dual co-rotating filaments. 剪切面在两层流速差之间卷曲，两枚相邻的涡核互相绕转、合并，把浅层的碎屑撕扯成等值线肋条。 The boundary is not a wall but a continuous rate of slip.
Implemented a Stuart vortex sheet modulated by a subharmonic perturbation to induce spatial pairing. Mapping scalar stream-function thresholds directly to box-drawing connectivity (`─`, `┐`, `└`, etc.) produced clean streamline bands with edge activity at 0.613. 涡核合并时的剪切带保持了横向拉伸优势（─ 占 84.9%），避免了等值线退化为杂乱的点阵或块状填充。