Ответ:
from tkinter import *
root = Tk()
c = Canvas(width=100, height=100, bg='white')
c.focus_set()
c.pack()
ball = c.create_oval(10, 10, 10, 10, fill='green')
c.bind('', lambda event: c.move(ball, 0, -2))
c.bind('', lambda event: c.move(ball, 0, 2))
c.bind('', lambda event: c.move(ball, -2, 0))
c.bind('', lambda event: c.move(ball, 2, 0))
root.mainloop()
Объяснение: