from machine import Pin
from utime import sleep
print("Hello, ESP32!")

led_red= Pin(23, Pin.OUT)
led_green= Pin(21, Pin.OUT)
led_blue= Pin(18, Pin.OUT)
led_yellow= Pin(5, Pin.OUT)
while True:
    # red : ON, Green : OFF, Blue : OFF, Yellow OFF
    led_red. on()
    led_green.off()
    led_blue.off()
    led_yellow.off
    sleep (0.5)

   # red : OFF, Green : ON, Blue : OFF, Yellow OFF
    led_red. off()
    led_green.on()
    led_blue.off()
    led_yellow.off()
    sleep (0.5) 

     # red : OFF, Green : OFF, Blue : ON, Yellow OFF
    led_red. off()
    led_green.off()
    led_blue.on()
    led_yellow.off()
    sleep (0.5) 

     # red : OFF, Green : OFF, Blue : OFF, Yellow ON
    led_red. off()
    led_green.off()
    led_blue.off()
    led_yellow.on()
    sleep (0.5)