As of 2018, Harry Falk refined his view by affirming that Brahmi was developed from scratch in a rational way at the time of Ashoka, by consciously combining the advantages of the pre-existing Greek script and northern Kharosthi script.[17] Greek-style letter types were selected for their "broad, upright and symmetrical form", and writing from left to right was also adopted for its convenience.[17] On the other hand, the Kharosthi treatment of vowels was retained, with its inherent vowel "a", derived from Aramaic, and stroke additions to represent other vowel signs.[17] In addition, a new system of combining consonants vertically to represent complex sounds was also developed.[17]