Left side
冫 — two strokes that look like ice droplets, originally
二 (two) marking 'second, next'. In
次 it functions less as 'ice' than as a sequence-marker: one done, the next up. The
冫 shape is also a 1956-style smoothing of an older
二. Same shape in
冰 (ice),
冷 (cold),
冬 (winter).