 <p>It's just wrong call parametters.</p> <p>If you want to change your code, this solution can help you.</p> <p>Class GUI just inherits from Canvas and doesn't implement anything.</p> <pre><code>from Tkinter import* root = Tk() class GUI(Canvas): '''inherits Canvas class (all Canvas methodes, attributes will be accessible) You can add your customized methods here. ''' def __init__(self,master,*args,**kwargs): Canvas.__init__(self, master=master, *args, **kwargs) polygon = GUI(root) polygon.create_polygon([150,75,225,0,300,75,225,150], outline='gray', fill='gray', width=2) polygon.pack() root.mainloop() </code></pre> <p>For more help add comments.</p>