Slot Roll

An odometer, not a scramble. Each column owns its own window inside durationInFrames (staggerInFrames frames apart), so the reel settles left to right, and each one walks the glyph pool forwards from its old character to its new one so it decelerates into the answer.

The pool is digits when both from and to are numeric and alphanumeric otherwise: an odometer that rolls through letters is not an odometer. Columns are padded to a common width and rendered monospace so the line cannot shift while it rolls.