Venetian Blind

a venetian blind over a page, tilted by its two cords. pull the left cord and the slats turn open, pull the right one and they shut.

key insight: the tilt runs down the blind instead of landing on every slat at once. each slat follows the one above it through its own exponential, the way a ladder tape carries the drum's turn down one rung at a time, so a hard tug reaches the foot a beat after the head and a slow pull shows no lag at all.

the slats are taller than their pitch, so a shut blind overlaps itself and no light gets through until each slat is past 27 degrees. that dead band at the start of a pull is what a real blind does too.