Assertion: ballpoint pen | /r/HasProperty | held
Facets:
value: in order to write
type: PURPOSE
value: vertically
type: MANNER
Source sentences:
text: Ballpoint pens have a tiny ball at the tip of the pen cylinder that uses capillary action to funnel the oil-based ink from the pen cartridge onto the paper; as a result, ballpoint pens do not need to be held vertically in order to write.