I'm attempting to learn Tkinter with the goal of being able to create a 'real-time' scope to plot data. As a test, I'm trying to draw a polygon on the canvas every time the 'draw' button is pressed. The triangle position is randomized. I have two problems: There is a triangle on the canvas as soon as the program starts, why and how do I fix this? It doesn't draw any triangles when I press the button, at least none that I can see. CODE from Tkinter import * from random import randint class App: def __init__(self,master): #frame = Frame(master) #frame.pack(side = LEFT) self.plotspc = Canvas(master,height = 100, width = 200, bg = "white") self.plotspc.grid(row=0,column = 2, rowspan = 5) self.button = Button(master, text = "Quit", fg = "red", \ command = master.quit) self.button.grid(row=0,column=0) self.drawbutton = Button(master, text = "Draw", command = \ self.pt([50,50])) self.drawbutton.grid(row = 0, column = 1) def pt(self, coords): coords[0] = coords[0] + randint(-20,20) coords[1] = coords[1] + randint(-20,20) x = (0,5,10) y = (0,10,0) xp = [coords[0] + xv for xv in x] yp = [coords[1] + yv for yv in y] ptf = zip(xp,yp) self.plotspc.create_polygon(*ptf) if _name_ == "_main_": root = Tk() app = App(root) root.mainloop() The code is formatting strangely within the code tags, I have no idea how to fix this.