import sys

from PyQt5.QtCore import Qt, QTimer
from PyQt5.QtWidgets import QWidget, QLabel, QPushButton, QGridLayout, QSizePolicy, QApplication

global QPushButton

button = QPushButton


class Window(QWidget):
    def __init__(self, *args, **kwargs):
        self.my_counter = 0   ## replaced  "1"
        self.my_counter1 = 0
        self.my_counter2 = 0
        QWidget.__init__(self, *args, **kwargs)

      #  self.label = QLabel("Q", self)    #original
        self.label = QLabel(self)
        self.label1 = QLabel(self)
        self.label2 = QLabel(self)
        self.label.setText("00")
        self.label.setSizePolicy(QSizePolicy.Expanding, QSizePolicy.Expanding)
        self.label.setAlignment(Qt.AlignCenter)
        self.label.setStyleSheet("QLabel {background-color: white; font-size: 30pt;}")


        self.label1 = QLabel(self)
        self.label1.setAlignment(Qt.AlignCenter)
        self.label1.setStyleSheet("QLabel {background-color: white; font-size: 30pt;}")
        self.label1.setText("00.")

        self.label2 = QLabel(self)
        self.label2.setAlignment(Qt.AlignCenter)
        self.label2.setStyleSheet("QLabel {background-color: pink; font-size: 30pt;}")
        self.label2.setText("00:")

        self.button = QPushButton(self)
        self.button.setStyleSheet("QPushButton {background-color: yellow; font-size: 15pt;}")
        self.button.setText("Start")

        self.layout = QGridLayout(self)
        self.layout.addWidget(self.label, 0, 4)
        self.layout.addWidget(self.label1, 0, 3)   # New label1
        self.layout.addWidget(self.label2, 0, 2)   # + New label2
        self.layout.addWidget(self.button, 3, 3)

        self.setLayout(self.layout)
        self.show()

    def local_button_handler(self):

        self.label.setText("%d" % self.my_counter)
        self.my_counter += 1

        if self.my_counter == 100:
            self.my_counter = 0
            self.my_counter1 += 1
            self.label1.setText("%d" % self.my_counter1 + ".")

            if self.my_counter1 == 60:
                self.label1.setText("00.")
                self.my_counter1 = 0
                self.my_counter2 += 1
                self.label2.setText("0"+"%d" % self.my_counter2 + ":")
            elif self.my_counter1  < 10:
                self.label1.setText("0" + "%d" % self.my_counter1 + ".")

        elif self.my_counter < 10:

            self.label.setText("0" +  "%d" % self.my_counter)

    def on_button_clicked(self):

        button.clicked.connect(win.local_button_handler())
        timer = QTimer()
        timer.timeout.connect(win.local_button_handler)
        timer.start(10)

    on_button_clicked

app = QApplication(sys.argv)
win = Window()
#
# timer = QTimer()
# timer.timeout.connect(win.local_button_handler)
# timer.start(10)
app.exec_()
sys.exit(app.exec_())