Another little shout-out for the genius of Tim Hunkin. Here he is demonstrating how a lockstitch sewing machine works by way of his "human sewing machine".
This is from The Secret Life of the Sewing Machine.
https://www.youtube.com/watch?v=8lwI4TSKM3Y
(h/t to @katiefenn for putting this in my head by way of her sewing post earlier.)

