respectively. There is also wide agreement that the u, r, k, h, s, b and o runes respectively correspond directly to V, R, C, H, S, B and O. The runes of uncertain derivation may either be original innovations, or adaptions of otherwise unneeded Latin letters. suggests that all 22 Latin letters of the classical Latin alphabet (1st Century, ignoring marginalized K) were adapted (ᚦ from D, ᛉ from Y, ᛜ from Q, Ƿ from P, ᛃ from G, ᛇ from Z), with two runes (ᛈ and ᛞ) left over as original Germanic innovations. There are conflicting scholarly opinions regarding the ᛖ (from E ?), ᚾ (from N ?), ᚦ (D ? or Raetic Θ ?), Ƿ (Q or P ?), ᛇ and ᛉ (both from either Z or Latin Y ?), ᛜ (Q ?), and ᛞ runes. Of the 24 runes in the classical futhark row attested from 400 (Kylver stone), ï, p and ŋ are unattested in the earliest inscriptions of c. 175 to 400, while e in this early period mostly takes a Π-shape, its M-shape () gaining prevalence only from the 5th century. Similarly, the s rune may have either three () or four () strokes (and more rarely five or more), and only from the 5th century does the variant with three strokes become prevalent. The "mature" runes of the 6th to 8th centuries tend to have only three directions of strokes, the vertical and two diagonal directions. Early inscriptions also show horizontal strokes: these appear in the case of e (mentioned above), but also in t, l, ŋ and h. Date and purpose of invention The general agreement dates the creation of the first runic alphabet to roughly the 1st century. Early estimates include the 1st century BC, and late estimates push the date into the 2nd century. The question is one of estimating the "findless" period separating the script's creation from the Vimose finds of c. 160. If either ï or z indeed derive from Latin Y or Z, as suggested by Odenstedt, the first century BC is ruled out, because these letters were only introduced into the Latin alphabet during the reign of Augustus. Other scholars are content to assume a findless period of a few decades, pushing the date into the early 2nd century. Pedersen (and with him Odenstedt) suggests a period of development of about a century to account for