docs: function(nodes) {
          var vertices;
          if(nodes === true) {
              vertices = [
                  this.components[0],
                  this.components[this.components.length-1]
              ];
          } else if (nodes === false) {
              vertices = this.components.slice(1, this.components.length-1);
          } else {
              vertices = this.components.slice();
          }
          return vertices;
      }