from tkinter import *
import _thread, time

def liigu():
  global x, y, d, dx, dy
  while y<200:
   x=x+dx
   y=y+dy
   ala.coords(ovaal, x, y, x+d, y+d)
   time.sleep(0.1)
   dy=dy+0.1

aken=Tk()
ala=Canvas(aken, width=400, height=300, bg='white')
ala.pack()

x=10
y=100
d=15
dx=1.0
dy=-2.0

ovaal=ala.create_oval(x, y, x+d, y+d, fill="blue")
_thread.start_new_thread(liigu, ())

aken.mainloop()