title: Sudoku GUI using QTableView (QT5)
body: <p>I'm trying to create a GUI for sudoku (for improving my QT5 skills).  I have decided to use for these purposes a QTableView. Up until that point there is no problem.</p>
  
  <p><a href="https://i.stack.imgur.com/mx8Og.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/mx8Og.png" alt="enter image description here"></a></p>
  
  <p>Now i want to draw grids to make 3x3 fields more visible. Is there any ideas, how i can do that?</p>