code: function(vertex, face) {
        if (vertex === face.outside) {
          // fix face.outside link
  
          if (vertex.next !== null && vertex.next.face === face) {
            // face has at least 2 outside vertices, move the 'outside' reference
  
            face.outside = vertex.next;
          } else {
            // vertex was the only outside vertex that face had
  
            face.outside = null;
          }
        }
  
        this.assigned.remove(vertex);
  
        return this;
      }
docs: Removes a vertex from the 'assigned' list of vertices and from the given face