polygon constant
polygon [Expects: http://schema.org/Text]
A polygon is the area enclosed by a point-to-point path for which the starting and ending points are the same. A polygon is expressed as a series of four or more space delimited points where the first and final points are identical.
Can be used on: http://schema.org/GeoShape
Implementation
static const polygon = IriTerm.prevalidated('http://schema.org/polygon');