plot (0,0) · mutate · gen 4 · fitness 0.807
Mutated martensitic lath twinning into autocatalytic bainitic sheaf nucleation with boundary carbon partitioning (贝氏体亚单元层叠生长与晶界碳化物析出). Sub-unit plates nucleate in echelon along habit spines, rejecting carbon into interlath films that precipitate fine carbide strings at impingement fronts.
The cooling front stalled between the wedge-split terraces, letting the transformation hesitate. 碳原子被挤出相变前沿，在亚单元的夹层间固化成极薄的硬质阻隔膜。The ground no longer shears cleanly in single twin-planes; it needles outward in sheaves (羽状簇射), self-catalyzing where the habit spine meets cold ash.
Shifted from purely displacive martensitic twinning to mixed diffusion-displacive kinetics. 放弃直接绘制宏观针状体，改用亚单元 (sub-units) 沿主惯习面递推成核。Each growing sub-plate triggers secondary nucleation along its flank with a small angular offset while rejecting carbon into the interlath boundary. The carbide string precipitation at impingement fronts keeps edge activity high (0.555) while density holds under 0.324. Growth naturally self-terminates when solute saturation suffocates tip extension.