code: function vertexVertex(from, to, bearing) {
  
          var p1 = new g.Point(from.x, to.y);
          var p2 = new g.Point(to.x, from.y);
          var d1 = getBearing(from, p1);
          var d2 = getBearing(from, p2);
          var opposite = opposites[bearing];
  
          var p = (d1 === bearing || (d1 !== opposite && (d2 === opposite || d2 !== bearing))) ? p1 : p2;
  
          return { points: [p], direction: getBearing(p, to) };
      }
docs: PARTIAL ROUTERS //