The pack manager can be a bit tricky to explain in words, and it can best be understood by playing with the code base. Fredrik Lundh, the author of Tkinter, asks us to imagine the root as an elastic sheet with a small opening at the center. The pack geometry manager makes a hole in the elastic sheet that is just large enough to hold the widget. The widget is placed along a given inner edge of the gap (the default is the top edge). It then repeats the process till all the widgets are accommodated.
Finally, when all the widgets have been packed in the elastic sheet, the geometry manager calculates the bounding box for all the widgets. It then makes the parent widget large enough to hold all the child widgets.
When ...
