The form of Latin S occurs from Greek Σ by dropping a person out from the four strokes of that letter. The (angular) S-shape made up of a few strokes existed to be a variant of the 4-stroke letter Σ already within the epigraphy of Western Greek alphabets, along with https://budnakedflower64530.tinyblogging.com/the-bud-naked-kits-diaries-75055203