Clairnote: An alternative music notation system
At a glance, this is a neat concept, but doesn't seem to come at the problem from the perspective of the most common users of music notation (experienced musicians); rather, it appears to have been written by somebody who was frustrated by trying to learn to read music. For experienced musicians, the priorities are a) legibility for sight-reading and transcription (which this system, with indistinguishable sitting/hanging notes and pervasive ledger lines fails) and b) musical context for expressive decisions, such as information about key, mode, modulation and harmonic content as hinted at by the key signatures and accidentals (which this system downplays as unnecessary).