I could stare at this illustration all day long.
If you ever wondered how a lockstitch sewing machine works, this is about as clear as it's going to get.
Basically, the needle pushes the top thread through the material, the lower thread is looped through the top thread, they are pulled tight and the whole process starts over again. Top quality machines can produce an astonishing 1600 stitches per minute!
Does anybody know of other images like this that I can stare at?