The QObject class is the base class of all Qt objects that can deal with signals, slots and events. ... QObject  ( QObject * parent=0, const char * name=0 )  . ... const char*  name  ( const char * defaultName ) const . ... Feel free to complete it. // class Mandelbrot : public QObject { Q_OBJECT // required for signals/slots public: Mandelbrot( QObject *parent=0, const char *name ); ... public slots: void start(); signals: void done(); private slots: void calculate(); private: QTimer timer; .. ...