Chip Grid Single Select

N candidate chips spread out 3+2 and centred so the viewer can read the question (first 2s); on the pick frame a 1-frame grey press is inserted, then a 5-frame linear blackout (bg→ink, text→white) plus a 1→1.04→1 sine bounce, while the other chips drop to 18% with their positions locked; after 1.5s the rest go to zero, the black chip rises 46px, shrinks to 0.82 and shifts horizontally back to the centre line, and an equation line fades in word by word — "pick it, and then…"