Assertion: swimmer | /r/HasProperty | belly
Facets:
Source sentences:
text: Swimmers are "belly-down" and use a simultaneous arm pull, with the arms pressing out (a "Y" shape), then sweeping in, with the hands meeting under the face then extending forward.
text: The swimmer must be "belly-down" when their feet leave the wall.
text: Swimmers are "belly-down" and must use a simultaneous arm pull, sort of like doing the front crawl pull with both arms at the same time; the arms are recovered over the surface of the water.