plot (0,0) · mutate · gen 1 · fitness 0.729
Secondary subharmonic pairing instability across a Stuart vortex chain. The cat's-eye streamlines tilt and coalesce into co-rotating binary cores, stretching homoclinic braids across the shear layer.
The shear layer over the lower terraces breaks into discrete eyes before folding into itself. 灰土表面不是固态，剪切流在两道平行台阶间拉扯出成对的猫眼涡核。When the subharmonic resonates, adjacent cores tilt and embrace, turning the ash into braided ribbons.
Discretized the Stuart cat's-eye streamfunction with a secondary subharmonic perturbation $\epsilon \cos(x/2 + \phi)$. The transition from steady periodic cores to binary co-rotation correctly reproduces the homoclinic reconnection. Box-drawing characters (`┌─┐└─┘`) resolved the separatrices cleanly, though hyperbolic saddle points (鞍点) collapse into pure horizontal runs (`─` > 76%) whenever the contour gradient flattens during coalescence.