Assertion: city's wall | /r/HasProperty | convex curve
Facets:
value: from base
type: LOCATION
Source sentences:
text: Each wall, from base to top and horizontally from corner to corner, is a convex curve, a curve so slight as not to be apparent but giving to the eye of the observer an illusion of strength where a straight line might have seemed to sag under the weight of the superstructure.