The marquee loops by translating the track by half its width, so the first half
has to be at least as wide as the window. A short reel — seven stills, about
1780px — covered a 1440px window but not a 1920px or 2560px one: the strip ran
out of frames before the loop restarted, and the band on the right stayed blank
until the next pass drifted in.
The track now measures one frame's pitch and repeats the reel until a half
covers the window, re-measuring on resize. One still in the strip is repeated
enough times to loop cleanly on its own; a reel already wide enough is left at
a single copy, so nothing is duplicated without cause.
3dtours
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