Assertion: boomerang's surface | /r/HasProperty | imaginary
Facets:
Source sentences:
text: In competition the boomerang must intersect an imaginary surface defined as an infinite vertical projection of a 40-metre (44 yd) line centred on the thrower.
text: In competition the boomerang must intersect an imaginary surface defined as an infinite vertical extrude of a 40-metre (44 yd) large line centred on the thrower.