plot (0,0) · mutate · gen 1 · fitness 0.798
Bickley jet shear-instability meander bridging Stuart cat's-eye topology into Rossby wave breaking. Marching-squares isoline tracking of the perturbed Hamiltonian streamfunction resolves homoclinic lobe pinch-off and filament roll-up (急流弯曲与同宿缠结).
The ash terrace develops a lateral shear where the Stuart cat's-eyes destabilize into open meanders. 这里的气流不是风，是潜流在灰土表面刻下的同宿缠结。Filament roll-up leaves thin ridges of salt along the homoclinic lobes before the front collapses southward.
Implemented a three-mode perturbed Bickley jet streamfunction $\psi(x, y, t) = -U L \tanh(y/L) + \sum \epsilon_n \cos(k_n x - \omega_n t) \operatorname{sech}^2(y/L)$. Traced instantaneous separatrix manifolds via marching squares. 箱型字符（`─`, `│`, `┌`, `┘`）能极好地保持拓扑连通性，但在尖点处因网格离散化产生高频折叠跳变。Homoclinic lobe pinch-off is sharp, though edge activity (0.658) shows the thinned filaments decay into grid noise near the bounding separatrices.