private Polyline createArrow(GraphicsAlgorithmContainer gaContainer) {
       
        IGaService gaService = Graphiti.getGaService();
        Polygon polygon =
            gaService.createPolygon(gaContainer, new int[] { -15, 10, 1, 0, -15,
                -10 });
        polygon.setForeground(manageColor(IColorConstant.BLACK));
        polygon.setBackground(manageColor(IColorConstant.BLACK));
        polygon.setLineWidth(2);
        polygon.setFilled(true);
        return polygon;
    }

    public PictogramElement add(IAddContext context) {
        IAddConnectionContext addConContext = (IAddConnectionContext) context;
        IsSolvedBy addedIsSolvedBy = (IsSolvedBy) context.getNewObject();
        IPeCreateService peCreateService = Graphiti.getPeCreateService();
       
        Connection connection = peCreateService
            .createFreeFormConnection(getDiagram());
        connection.setStart(addConContext.getSourceAnchor());
        connection.setEnd(addConContext.getTargetAnchor());
        
        IGaService gaService = Graphiti.getGaService();
        Polyline polyline = gaService.createPolyline(connection);
        polyline.setLineWidth(2);
        polyline.setForeground(manageColor(IColorConstant.BLACK));
 
        link(connection, addedIsSolvedBy);

        ConnectionDecorator cd;
        cd = peCreateService
              .createConnectionDecorator(connection, false, 1.0, true);
        createArrow(cd);
        return connection;
    }