public Iterable<EleConnector> getEleConnectors() {
calculateOutlineIfNecessary();
if (connectors == null) {
connectors = new EleConnectorGroup();
connectors.add(new EleConnector(lowerLeft, node, ON));
connectors.add(new EleConnector(lowerCenter, node, ON));
connectors.add(new EleConnector(lowerRight, node, ON));
connectors.add(new EleConnector(upperLeft, null, ON));
connectors.add(new EleConnector(upperCenter, null, ON));