from PyQt4 import QtCore, QtGui, Qt
from PyQt4.QtGui import QApplication, QMainWindow
import sys, math

class MyMainScreen(QMainWindow):
    def __init__(self, parent=None):
        QtGui.QMainWindow.__init__(self, parent)

        self.timer  = QtCore.QTimer(self)
        self.timer.setInterval(100)
        self.timer.timeout.connect(self.blink)
        self.timer.start()

        self.resize(500, 500)
        self.centralwidget = QtGui.QWidget(self)
        self.horizontalLayout = QtGui.QHBoxLayout(self.centralwidget)

        self.setCentralWidget(self.centralwidget)
        self.menubar = QtGui.QMenuBar(self)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 500, 22))

        self.setMenuBar(self.menubar)

        self.statusbar = QtGui.QStatusBar(self)
        self.setStatusBar(self.statusbar)
        QtCore.QMetaObject.connectSlotsByName(self)

        self.n = 0

    def blink(self):
        self.n += 0.1
        self.n = self.n % 20
        self.repaint()

    def paintEvent(self, event):
        painter = QtGui.QPainter(self)
        painter.setRenderHint(QtGui.QPainter.Antialiasing)
        painter.setRenderHint(QtGui.QPainter.HighQualityAntialiasing)
        painter.setPen(QtGui.QPen(QtCore.Qt.red, 2))

        step = 2
        amp = (self.height()/2)*0.8
        for i in range(0, self.width(), step):
            y0 = round(self.height()/2 + amp * math.sin(2*math.pi*self.n*(i/180)))
            y1 = round(self.height()/2 + amp * math.sin(2*math.pi*self.n*((i+step)/180)))
            painter.drawLine(QtCore.QLine(i, y0, i+step, y1))

if __name__ == "__main__":
    app = QApplication(sys.argv)
    mainscreen = MyMainScreen()
    mainscreen.show()
    app.exec_()