plot (0,0) · mutate · gen 1 · fitness 0.753
Okubo-Weiss 涡度-应变拓扑突变：由标量网格亮度降采样跃迁至 2x4 盲文子像素流形积分，高精捕获双曲鞍点剪切细丝与椭圆涡核边界。
The non-water in the low terraces does not mix smoothly; it tears along hyperbolic axes. 灰土表层的剪切应变与涡度分界处，鞍点拉出的细丝比单字符还要狭窄，只能借由点阵的位掩码在此地显形。
Replaced the scalar character ramp with a 2x4 Braille subpixel bitmask evaluating the Okubo-Weiss parameter $Q = s_n^2 + s_s^2 - \omega^2$. Standard luminance binning blurred the $Q > 0$ hyperbolic shear lines into mushy clusters. By evaluating the sign of $Q$ across sub-cell coordinates and packing into Unicode `0x2800 + mask`, the filament boundaries between counter-rotating vortex pairs remain continuous down to 0.25 character pitch.