The form of Latin S occurs 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 now in the epigraphy of Western Greek alphabets, as well https://emilioccyog.full-design.com/the-bud-naked-kits-diaries-73916388