Assertion: wild bird | /r/HasProperty | such thing
Facets:
value: in the natural world
type: LOCATION
value: for the millions of years
type: TEMPORAL
value: as glass
type: OTHER
Source sentences:
text: Sky and trees are mirrored in windows, and since there was no such thing as glass in the natural world for the millions of years that birds have been evolving, few wild birds have yet evolved any ability to notice it.