from tkinter import *
from random import randrange, randint

x=randint(0, 200)
y=randint(0, 200)
r=15
mult = 1
mult2 = 1

mouvement = False

def demarrer():
    global mouvement
    if mouvement == False:
        mouvement = True
    else:
        mouvement = False

def deplace():
    global x, y, mouvement, mult, mult2

    if mouvement==True:
        if(y + 15) >= 200:
            mult *= -1
        if (y - r) <= 0 and mult==1:
            mult *= -1
        y -= mult * 5

        if (x + 15) >= 200:
            mult *= -1
        if (x - r) <= 0 and mult2==1:
            mult *= -1
        x += mult * 5
        can.coords(oval, x - mult2 * r, y - mult * r, x + mult2 * r, y + mult * r)
    fen.after(25,deplace)


fen = Tk()
can = Canvas(fen, bg='white', height=200, width=200)
can.pack(side=RIGHT)
bout1 = Button(fen,text='Quitter',command=fen.destroy)
bout1.pack(side=BOTTOM) #Comme Christine Boutin

boutonDemarrer = Button(fen, text='Demarrer',command=demarrer)
boutonDemarrer.pack(side=TOP)

c=['red','green','blue','yellow','orange']
i=randrange(5)
oval = can.create_oval(x-r, y-r, x+r, y+r, fill=c[i], outline=c[i])
fen.after(50,deplace)
fen.mainloop()