Snowflakes 1

#!/usr/bin/env python
import sys
from functools import partial
from itertools import chain
from random import randrange
from subprocess import check_output
from time import sleep


clear_screen = partial(sys.stdout.write, '\033[2J')


def cursor_at(row, column):
    sys.stdout.write('\033[{0};{1}H'.format(row, column))


cursor_home = partial(cursor_at, 0, 0)


def write_at(row, column, text):
    cursor_at(row, column)
    sys.stdout.write(text)


def main():
    row_count, column_count = map(int, check_output(['stty', 'size']).split())
    flakes = list()
    clear_screen()
    while True:
        next_flakes = list()
        for row, column in chain(flakes, [(0, randrange(column_count))]):
            if row <= row_count:
                write_at(row, column, ' ')
                row += 1
                next_flakes.append((row, column))
                write_at(row, column, u'\u2743 ')
                cursor_home()
        flakes = next_flakes
        sys.stdout.flush()
        sleep(0.1)


if __name__ == '__main__':
    main()