The shape of Latin S occurs from Greek Σ by dropping just one out of your 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 inside the epigraphy of Western Greek alphabets, along with https://israelljcwm.gynoblog.com/30709923/what-does-bud-naked-mean