The form of Latin S arises from Greek Σ by dropping just one out of the 4 strokes of that letter. The (angular) S-condition 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://israelypesh.ssnblog.com/30642308/the-smart-trick-of-bud-naked-kits-that-nobody-is-discussing