from machine import * 
from time import * 

led1 = Pin(1,Pin.OUT) 
led2 = Pin(3,Pin.OUT) 
led3 = Pin(7,Pin.OUT) 
led4 = Pin(10,Pin.OUT) 

while True: 
   led2.value(0)
   led3.value(0)
   led4.value(0)
   for i in range (2): 
       led1.value(0)
       sleep(0.5)
       led1.value(1) 
       sleep(0.5) 
   sleep(2) 

   led1.value(0)
   led3.value(0)
   led4.value(0)
   for i in range (2): 
       led2.value(0)
       sleep(0.5)
       led2.value(1) 
       sleep(0.5) 
   sleep(2) 

   led2.value(0)
   led4.value(0)
   led1.value(0)
   for i in range (2): 
       led3.value(0)
       sleep(0.5)
       led3.value(1) 
       sleep(0.5) 
   sleep(2) 

   led3.value(0)
   led1.value(0)
   led2.value(0)
   for i in range (2): 
       led4.value(0)
       sleep(0.5)
       led4.value(1) 
       sleep(0.5) 
   sleep(2)