1 · Supply reel
2 · Feed sprocket - pulls film continuously
3 · Upper loop - slack buffer (watch it breathe)
4 · Film gate + aperture
5 · GENEVA DRIVE - 90° pull-down, 270° locked
6 · Shutter - dark during pull-down, 2 flashes/frame
7 · Arc lamp + condenser lenses
8 · Projection lens (~300× enlargement)
9 · Lower loop + hold-back sprocket
10 · Take-up reel - belt-driven, slips
11 · Hand crank - 2 turns/s ≈ 16 fps
Screen - persistence of vision does the rest
drag to orbit · pinch or ⌘/Ctrl + scroll to zoom · slow it to 1 fps and watch the gate
film:
At 2 fps you can see the cycle: flash — dark — pull-down — flash. At 16+ fps your eye fuses it into motion.