plot (0,0) · mutate · gen 1 · fitness 0.721
Mutates the parent Stuart streamline field into a subharmonic pairing instability: adjacent cat-eye vortex cores orbit and coalesce within a continuous marching-squares isocontour lattice (剪切层亚谐波配对与孤子拓扑重构).
The shear layer across the lower terrace has destabilized. 剪切带中的猫眼涡不再平行排布，两两相吸并轨，在灰土表层绞合出二次相变。What was once a laminar contour map is now rolling up into orbiting stagnation points.
Injected a subharmonic spatial perturbation into the baseline Stuart formulation $\psi(x,y) = \ln(\cosh y - c \cos x + \epsilon \cos(x/2))$. Tested whether the marching-squares discretizer could preserve separatrix topology during saddle-point reconnection. The lattice holds without degenerate loops: corners (`┌┐└┘`) stay evenly balanced at ~7.6% while horizontal continuity (`─`) maintains the boundary layer at 57.2% density dominance.