Glyphs have to be written in an orientation; bidirection (or higher symmetric) layouts would impose either writing the words left to right & right to left, whic

Glyphs have to be written in an orientation; bidirection (or higher symmetric) layouts would impose either writing the words left to right & right to left, which would cause smearing when writing with ink with a dominant hand, or mirroring the glyphs themselves, which would make reading & writing words much more difficult.