from microbit import *
# control four LEDs on port 13, 14, 15 and 16
# chase the LEDs
while True: 
    pin13.write_digital(1) 
    sleep(300)
    pin13.write_digital(0) 
    pin14.write_digital(1) 
    sleep(100)
    pin14.write_digital(0) 
    pin15.write_digital(1) 
    sleep(100)
    pin15.write_digital(0) 
    pin16.write_digital(1) 
    sleep(300)
    pin16.write_digital(0) 
    pin15.write_digital(1) 
    sleep(100)
    pin15.write_digital(0) 
    pin14.write_digital(1) 
    sleep(100)
    pin14.write_digital(0)