from machine import Pin
from utime import sleep

b0=Pin(0,Pin.OUT)
b1=Pin(1,Pin.OUT)
b2=Pin(2,Pin.OUT)
b3=Pin(3,Pin.OUT)

bulb=[b0,b1,b2,b3]

c=0

def dec_to_bin(x):
  r=[]
  while(x>0):
    r.append(x%2)
    x=x//2
  return r

while True:
  b=dec_to_bin(c)
  on=0
  for i in b:
    if i==1:
      bulb[on].value(1)
    on+=1
  print("Turned on for ",c,b)
  sleep(1)
  for b in bulb:
    b.value(0)
  c+=1
  c=c%16