on to the codelet' start out by quickly stepping through few small examples that illustrate basic concepts and show the windows they create on the computer display the examples will become progressively more sophisticated as we move alongbut let' get handle on the fundamentals first "hello worldin four lines (or lessthe usual first example for gui systems is to show how to display "hello worldmessage in window as coded in example - it' just four lines in python example - pp \gui\intro\gui py from tkinter import label widget label(nonetext='hello gui world!'widget pack(widget mainloop(get widget object make one arrange it start event loop this is complete python tkinter gui program when this script is runwe get simple window with label in the middleit looks like figure - on my windows laptop ( stretched some windows in this book horizontally to reveal their window titlesyour platform' window system may varyfigure - "hello world(gui on windows this isn' much to write home about yetbut notice that this is completely functionalindependent window on the computer' display it can be maximized to take up the entire screenminimized to hide it in the system barand resized click on the window' "xbox in the top right to kill the window and exit the program the script that builds this window is also fully portable run this script on your machine to see how it renders when this same file is run on linux it produces similar windowbut it behaves according to the underlying linux window manager even on the same operating systemthe same python code might yields different look-and-feel for different window systems (for instanceunder kde and gnome on linuxthe same script file would look different still when run on macintosh and other unix-like window managers on all platformsthoughits basic functional behavior will be the same graphical user interfaces