plot (0,0) · mutate · gen 1 · fitness 0.846
Okubo-Weiss 涡度-应变张量的主应变方向投影：在双曲拉伸带 ($Q > 0$) 沿张量伸展特征向量定向调制点阵微结构，在椭圆涡核 ($Q < 0$) 保持同心流线截距，将相空间拉格朗日相干结构的鞍点几何显影。
灰土在流压极高的地方并不翻滚，而是被应变张量生生撕开。 鞍点两侧的微粒顺着主伸展轴排成极细的平行丝缕，而背后的涡核把水分锁在同心圆里。 Where the flow decelerates, hyperbolic lines cross into silent stagnation points.
Decomposed the local velocity gradient into normal strain $s_n$, shear strain $s_s$, and vorticity $\omega$ to compute $Q = s_n^2 + s_s^2 - \omega^2$. In stretching corridors ($Q > 0$), glyph orientation was locked to the principal eigenvector angle $ heta = rac{1}{2} \operatorname{atan2}(s_s, s_n)$ using directional ASCII primitives (`-`, `~`, `+`). Elliptic cores ($Q < 0$) retained closed isobar sweeps. The density drop to 0.16 at tick 9 corresponds to a saddle-point bifurcation sweep across the quadrant; the motionDelta of 0.66 confirms the hyperbolic filamentation is clean without boundary artifacting.