from microbit import *

def dim_display():
    for x in range(0, 5):
        for y in range(0, 5):
            c = display.get_pixel(x, y)
            if c > 1:
                display.set_pixel(x, y, c - 1)

def set_brightness(b):
    for x in range(0, 5):
        for y in range(0, 5):
            if display.get_pixel(x, y) > 0:
                display.set_pixel(x, y, b)


def brighten_display():
    for x in range(0, 5):
        for y in range(0, 5):
            c = display.get_pixel(x, y)
            if c > 0 and c < 9:
                display.set_pixel(x, y, c + 1)

def pulse():
    d = 80
    for x in range(3):
        brighten_display()
        sleep(d)
        d -= 10

    for x in range(3):
        dim_display()
        sleep(d)
        d += 10

    d = 80
    for x in range(7):
        brighten_display()
        sleep(d)
        d -= 10
    sleep(200)

    d = 40
    for x in range(7):
        dim_display()
        sleep(d)
        d += 5
    sleep(100)


display.show(Image.HEART)
set_brightness(2)

while True:
    pulse()