Assertion: concertina's bellow | /r/HasProperty | compressed
Facets:
Source sentences:
text: Some produce sound as the bellows are being compressed only, while others can make sounds in both directions.
text: The instrument is bisonoric, meaning that each button corresponds to two notes: one when the bellows is compressed, and another when it is expanded.
text: This means that the selected note can be played whether the bellow is compressed or expanded, so a sequential chain of notes can be played without the necessity to alter the direction of the bellow.