postavicka 

import tkinter as tk

class SmajlikApp:

   def __init__(self, koren):

       self.koren = koren

       self.koren.title("Smajlik")

       self.platno = tk.Canvas(koren, width=600, height=400, bg="white")

       self.platno.pack()

       self.smajlik = self.platno.create_oval(50, 50, 100, 100, fill="yellow")

       self.platno.focus_set()

       self.platno.bind("<KeyPress>", self.na_stlacenie_klavesy)

   def na_stlacenie_klavesy(self, udalost):

       x1, y1, x2, y2 = self.platno.coords(self.smajlik)

       if udalost.keysym == 'Left' and x1 > 0:

           self.platno.move(self.smajlik, -10, 0)

       elif udalost.keysym == 'Right' and x2 < 600:

           self.platno.move(self.smajlik, 10, 0)

       elif udalost.keysym == 'Up' and y1 > 0:

           self.platno.move(self.smajlik, 0, -10)

       elif udalost.keysym == 'Down' and y2 < 400:

           self.platno.move(self.smajlik, 0, 10)

       elif udalost.char == 'r':

           self.platno.itemconfig(self.smajlik, fill="red")

       elif udalost.char == 's':

           self.platno.itemconfig(self.smajlik, fill="yellow")

if __name__ == "__main__":

   koren = tk.Tk()

   app = SmajlikApp(koren)

   koren.mainloop()