from machine import Pin
from time import sleep

while True:
    # Even-numbered LEDs (GP2, GP4, ..., GP10)
    for i in range(2, 11, 2):  # Start from 2 to 10 with step of 2
        led = Pin(i, Pin.OUT,)
        led.value(1)  # Turn ON
        sleep(0.3)
        led.value(0)  # Turn OFF

    # Odd-numbered LEDs (GP9, GP7, ..., GP1) in reverse
    for i in range(9, 0, -2):  # Start from 9 down to 1 with step of -2
        led = Pin(i, Pin.OUT)
        led.value(1)  # Turn ON
        sleep(0.3)
        led.value(0)  # Turn OFF