Abugida
Inspired by shorthand and Shavian, use simple shapes for the consonants, ideally moving left to right (like a dash).
'a' is the implicit vowel.
'i' and 'u' should attach only to the preceding consonants, given that they always finish a root (apart from proper nouns).
'ā', 'ē', 'ī', 'ō' and 'ū' should connect to both sides, given that they can never finish a root.