from tkinter import *
import random

vx=10
vy=0

def move():
    canvas.move(head, vx, vy)
    window.after(50,move)
    cc = canvas.coords(coin)
    if canvas.coords(head) == cc:
        tx = random.randrange(0,50)*10
        ty = random.randrange(0,50)*10
        canvas.move(coin, tx-cc[0], ty-cc[1])


def go_left(e):
    global vx
    global vy
    vx=-10
    vy=0

def go_right(e):
    global vx
    global vy
    vx=10
    vy=0

def go_up(e):
    global vx
    global vy
    vx=0
    vy=-10

def go_down(e):
    global vx
    global vy
    vx=0
    vy=10

window= Tk()
canvas = Canvas(window, width=500,height=500,background="white")
canvas.pack()
#for i in range(50):
 #   canvas.create_line(i*10,0,i*10,500,fill ="#777777")
 #   canvas.create_line(0,i*10,500,i*10)
head = canvas.create_rectangle(250,250,260,260,fill='magenta')

window.after(100,move)

window.bind('<Left>', go_left)
window.bind('<Right>', go_right)
window.bind('<Up>', go_up)
window.bind('<Down>', go_down)
tx = random.randrange(0,50)*10
ty = random.randrange(0,50)*10
coin=canvas.create_rectangle(tx,ty,tx+10,ty+10,fill='lightblue')

mainloop()