question: public S2Loop ( final List < S2Point > vertices ) { this . numVertices = vertices . size ( ) ; this . vertices = new S2Point [ numVertices ] ; this . bound = S2LatLngRect . full ( ) ; this . depth = 0 ; vertices . toArray ( this . vertices ) ; initOrigin ( ) ; initBound ( ) ; initFirstLogicalVertex ( ) ; }
target:  Initialize a loop connecting the given vertices. The last vertex is implicitly connected to the first. All points should be unit length. Loops must have at least 3 vertices.