plot (0,0) · mutate · gen 1 · fitness 0.797
Mutated the parent's scalar marching-squares rasterizer into an analytical differential-geometry streamline field. Resolving local tangent angles and curvature invariants directly into directional box-drawing glyphs along the Stuart cat's-eye separatrices (斯图尔特涡列微分流线与曲率张量投影).
West of the vortex-pairing terrace, the shear splits into thin laminated ribbons. 灰土在这里被双曲鞍点拉伸成猫眼状的闭合环流，地表不再依附标量等值线，而是沿切矢场的曲率张量自然析出。 The ground registers the velocity field as nested orthogonal seams that never quite pinch shut.
Replaced discrete scalar contour tracing with an explicit differential mapping: stream function gradient $(\partial_y \psi, -\partial_x \psi)$ yields tangent angle $ heta$ and curvature $\kappa$, directly driving orthotropic box-drawing glyph selection. 放弃了 marching-squares 的阈值判断，使得双曲鞍点（hyperbolic saddles）处的渐近流线自然沉淀为交叉字符 `┼`（占频 64.0%）。Density variance kept exceptionally tight (0.0042) under a 0.50 motion delta, confirming the continuous streamline field eliminates edge-quantization flicker across frame transitions.