from machine import Pin,Timer
import time 
import random

led1=Pin(0,Pin.OUT)
led2=Pin(1,Pin.OUT)
led3=Pin(2,Pin.OUT)
led4=Pin(3,Pin.OUT)
led5=Pin(4,Pin.OUT)
led6=Pin(5,Pin.OUT)
led7=Pin(6,Pin.OUT)
led8=Pin(7,Pin.OUT)

while True:
  t=0.5
  led1.off()
  led2.off()
  led3.off()
  led4.off()
  led5.off()
  led6.off()
  led7.off()
  led8.off()
  for n1 in reversed(range (1,9)):
    time.sleep(t)
    if n1==1:
        led1.on() 
        
       
    
    if n1==2:
        led2.on() 
        
        
    if n1==3:
        led3.on() 
        
        
    if n1==4:
        led4.on() 
        

    if n1==5:
        led5.on() 
        
        
    if n1==6:
        led6.on() 
        

    if n1==7:
        led7.on() 
        

    if n1==8:
        led8.on()