S NO FURTHER A MYSTERY

The form of Latin S arises from Greek Σ by dropping just one out in the 4 strokes of that letter. The (angular) S-condition composed of 3 strokes existed to be a variant in the 4-stroke letter Σ already from the epigraphy of Western Greek alphabets, along with the a few and 4 strokes variants existed alongside one another inside the classical Etr