S NO FURTHER A MYSTERY

The shape of Latin S occurs from Greek Σ by dropping 1 out in the 4 strokes of that letter. The (angular) S-shape composed of 3 strokes existed as a variant on the 4-stroke letter Σ presently during the epigraphy of Western Greek alphabets, as well as three and four strokes variants existed along with one another from the classical Etruscan alpha