Fire animation in console using Python

fire.py

import curses, random

screen  = curses.initscr()
width   = screen.getmaxyx()[1]
height  = screen.getmaxyx()[0]
size    = width*height
char    = [" ", ".", ":", "^", "*", "x", "s", "S", "#", "$"]
b       = []
curses.curs_set(0)
curses.start_color()
curses.init_pair(1,0,0)
curses.init_pair(2,1,0)
curses.init_pair(3,3,0)
curses.init_pair(4,4,0)
screen.clear

for i in range(size+width+1): b.append(0)
while 1:
        for i in range(int(width/9)): b[int((random.random()*width)+width*(height-1))]=65
        for i in range(size):
                b[i]=int((b[i]+b[i+1]+b[i+width]+b[i+width+1])/4)
                color=(4 if b[i]>15 else (3 if b[i]>9 else (2 if b[i]>4 else 1)))
                if(i<size-1):   screen.addstr(  int(i/width),
                                                i%width,
                                                char[(9 if b[i]>9 else b[i])],
                                                curses.color_pair(color) | curses.A_BOLD )
        screen.refresh()
        screen.timeout(30)
        if (screen.getch()!=-1): break
curses.endwin()