import time
time.sleep(0.1) # Wait for USB to become ready
from machine import Pin 
import random

green = Pin(1,Pin.OUT)
yellow = Pin(2,Pin.OUT)
red = Pin(6,Pin.OUT)

while True:
    n=random.random()
    print(n)
    if n>=0.75:
        green.on()
        time.sleep(0.5)
        green.off()
        time.sleep(0.5)
    elif n<0.75 and n>=0.5:
        yellow.on()
        time.sleep(0.5)
        yellow.off()
        time.sleep(0.5)
    else:
        red.on()
        time.sleep(0.5)
        red.off()
        time.sleep(0.5)