The shape 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://bud-naked-pre-rolls20863.bloggactif.com/32301727/s-no-further-a-mystery