Assertion: lamp's light | /r/CapableOf | use symmetrical optics
Facets:
value: rotationally
type: MANNER
Source sentences:
text: Despite its complexity, it is a more useful measure than watts, because it defines how much usable light is shed in a given place: a dynamo headlight designed for road use and focused for seeing the road makes more efficient use of the power of the lamp than lights using rotationally symmetrical optics.