from turtle import *

c = float(input("Carré = "))
color("white")
goto(-1/2*c,-1/2*c)
color("black")
for i in range (4):
    forward(c)
    left(90)
color("white")
goto(1/10000*c,1/128*c)
color("black")
circle(4/10*c)
mainloop()