Tab Bar Part 4

Basics: stage 470×222px, background #13131C, all coordinates in px from the stage's top-left, everything clipped to the stage (top corners rounded 40px). It plays by itself in a seamless loop. T = seconds since the video start (12s video). u = (T + 0.25) mod 4 (the first frame is already 0.25s after a tap). A tap every second at u = 0, 1, 2, 3 (video T = 0.75, 1.75, 2.75 …), selecting the tabs SEL = [3, 1, 2, 0] (tab 0 = leftmost): lastTap(u): k = floor(u), dt = u − k (seconds since the last tap), to = SEL[k], from = SEL[(k+3) mod 4]. So the moves are 3, 2, 1, 2 tabs long.

A frosted glass pill whose two ends spring separately, so it stretches while it travels; it frosts over while moving and clears when it lands. 
- Leading end spring springF(19, 0.55), trailing end springF(11, 0.72) (the leading end is the side it moves toward). Left x = max(38, tab x(left position) − 43), right x = min(432, tab x(right position) + 43); w = right − left; s = clamp((w − 86)/86); height h = 64·(1 − 0.1s). Center = middle of the two ends, y 148; lens center = the same point.
- Speed sn = clamp(|average of the two velAt values| / 7). glass blur = 1.5 + 6.5·sn; frost: right after the horizontal tint and before the vertical gloss, fill the box with rgba(225,225,245, 0.14·sn). Fixed icons.