from machine import Pin
from utime import sleep

r = Pin(10, Pin.OUT)
g = Pin(9, Pin.OUT)
b = Pin(8, Pin.OUT)

while True:
    r.on()
    sleep(1)
    r.off()

    g.on()
    sleep(1)
    g.off()

    b.on()
    sleep(1)
    b.off()