12-entry sorted sub-sequence → stock attention → scatter back to N = 16. Shift = pool − 1: L0 → no shift, L1 → +1, L2 → +3 (pool taken w.r.t. the base sequence).
Sorted sub-sequence
phase 1 / 5
L0 → 1 base pos (no shift)L1 → 2 base pos (+1)L2 → 4 base pos (+3)