title: How to create a grid on tkinter in python?
body: <p>I  managed to create a function that with a given radius, starting point and a number of points. It will create a big circle and withing this circle it will create 4 small circles.
  I want to add a grid on the background that will show the Y and X axis in TKinter every 100 pixels apart starting from the top left. The coordinate origin should be the top left corner.
  For example if the screen is 300x300 then the window will have 3 lines (at 100, 200 and 300) on his X axis going from left to right and top up to bottom. 
  A grid as a coordinate system.</p>
  
  <p>Example of how I create a normal line. I use a line class which contains 2 points start point and end point:</p>
  
  <pre><code>rootWindow = Tkinter.Tk()
  rootFrame = Tkinter.Frame(rootWindow, width=1000, height=800, bg="white")
  rootFrame.pack()
  canvas = Tkinter.Canvas(rootFrame, width=1000, height=800, bg="white")
  canvas.pack() 
  def draw_line(l):
      "Draw a line with its two end points"
      draw_point(l.p1)
      draw_point(l.p2)
      # now draw the line segment
      x1 = l.p1.x
      y1 = l.p1.y
      x2 = l.p2.x
      y2 = l.p2.y
      id = canvas.create_line(x1, y1, x2, y2, width=2, fill="blue")
      return id
  </code></pre>