import tkinter
import random
canvas=tkinter.Canvas(width=500,height=110,bg='darkblue')
canvas.pack()
def lopticky():
    global a1, a2
    b1=10
    if spusti==1:
        canvas.delete('L1','L2')
        canvas.create_oval(a1,b1,a1+10,b1+10,fill='orange',tag='L1')
        canvas.create_oval(a2,b1,a2-10,b1+10,fill='red',tag='L2')
        if a1+10<a2-10:
            ka1=random.randrange(5,11)
            ka2=random.randrange(5,11)
            a1=a1+ka1
            a2=a2-ka2
            canvas.after(100,lopticky)
        else:
            canvas.create_text(250,60,text='BUM',font=('Arial',50,'bold'),fill='yellow')
def klik(lave):
    x=lave.x
    y=lave.y
    global spusti
    if 10<x<110 and 30<y<60:
        spusti=1
    elif 10<x<110 and 70<y<100:
        spusti=0
    lopticky()

a1=1
a2=500
canvas.create_rectangle(10,30,110,60,fill='white',width=3)
canvas.create_rectangle(10,70,110,100,fill='white',width=3)
canvas.create_text(60,45,text='START',font=('Arial',15))
canvas.create_text(60,85,tex='STOP',font=('Arial',15))
canvas.bind('<Button-1>',klik)