Assertion: ordinary mirror | /r/HasProperty | placed against wall
Facets:
value: usually
type: TEMPORAL
Source sentences:
text: Also, rapping on the mirror should provide an aural clue: ordinary mirrors have backings and are usually placed against walls, so rapping on them will generally produce dull thuds; transparent mirrors are set into walls with open areas behind them, so rapping on them should produce much more open, hollow sounds.