Как распараллелить потоки

#include "Classes.h"

void Event::Show(QString str) {
    qDebug() << str;
}

MainThread::MainThread() {
    m_event = new Event();
}

MainThread::~MainThread() {
    delete m_event;
    for (int i = 0; i < 3; i++) {
        delete threads;
    }
}

void MainThread::Run() {
    for (int i = 0; i < 3; i++) {
        ChildThread *child = new ChildThread(i + 1);
        child->setNumber(i + 1);
        child->setEvent(m_event);
        threads.push_back(child);
        child->start();
    }
}

ChildThread::ChildThread(int timer, QObject *parent) : QThread(parent) {
    startTimer(timer * 1000);
}

void ChildThread::setNumber(uint number) {
    m_number = number;
}

void ChildThread::setEvent(Event *event) {
    m_event = event;
}

void ChildThread::timerEvent(QTimerEvent *event) {
    //m_number++;
    m_event->Show(QString("Run from %1 thread (1)").arg(m_number));

    sleep(m_number * 2);

    m_event->Show(QString("Run from %1 thread(2)").arg(m_number));

    sleep(m_number * 2);

    m_event->Show(QString("Run from %1 thread(3)").arg(m_number));

    sleep(m_number * 2);

    m_event->Show(QString("Run from %1 thread(4)").arg(m_number));
}