python implementation of fireworks applet

'''
FIREWORKS SIMULATION WITH TKINTER
*self-containing code
*to run: simply type python  in your console
*compatible with both Python 2 and Python 3
*Dependencies: tkinter, Pillow (only for background image)
*The design is based on high school physics, with some small twists only for aesthetics purpose
 
import tkinter as tk
#from tkinter import messagebox
#from tkinter import PhotoImage
from PIL import Image, ImageTk
from time import time, sleep
from random import choice, uniform, randint
from math import sin, cos, radians
# gravity, act as our constant g, you can experiment by changing it
GRAVITY = 0.05
# list of color, can choose randomly or use as a queue (FIFO)
colors = ['red', 'blue', 'yellow', 'white', 'green', 'orange', 'purple', 'seagreen','indigo', 'cornflowerblue']
Generic class for particles
particles are emitted almost randomly on the sky, forming a round of circle (a star) before falling and getting removed
from canvas
Attributes:
 - id: identifier of a particular particle in a star
 - x, y: x,y-coordinate of a star (point of explosion)
 - vx, vy: speed of particle in x, y coordinate
 - total: total number of particle in a star
 - age: how long has the particle last on canvas
 - color: self-explantory
 - cv: canvas
 - lifespan: how long a particle will last on canvas
class part:
 def __init__(self, cv, idx, total, explosion_speed, x=0., y=0., vx = 0., vy = 0., size=2., color = 'red', lifespan = 2, **kwargs):
   = idx
   = x
   = y
  self.initial_speed = explosion_speed
   = vx
   = vy
   = total
   = 0
   = color
   = cv
   = .create_oval(
   x - size, y - size, x + size,
   y + size, fill=)
   = lifespan
 def update(self, dt):
   += dt
  # particle expansions
  if () and ():
   move_x = cos(radians(*360/))*self.initial_speed
   move_y = sin(radians(*360/))*self.initial_speed
   (, move_x, move_y)
    = move_x/(float(dt)*1000)
  # falling down in projectile motion
  elif ():
   move_x = cos(radians(*360/))
   # we technically don't need to update x, y because move will do the job
   (,  + move_x, +GRAVITY*dt)
    += GRAVITY*dt
  # remove article if it is over the lifespan
  elif  is not None:
   ()
    = None
 # define time frame for expansion
 def expand (self):
  return  <= 1.2
 # check if particle is still alive in lifespan
 def alive(self):
  return  <= 
Firework simulation loop:
Recursively call to repeatedly emit new fireworks on canvas
a list of list (list of stars, each of which is a list of particles)
is created and drawn on canvas at every call, 
via update protocol inside each 'part' object 
def simulate(cv):
 t = time()
 explode_points = []
 wait_time = randint(10,100)
 numb_explode = randint(6,10)
 # create list of list of all particles in all simultaneous explosion
 for point in range(numb_explode):
  objects = []
  x_cordi = randint(50,550)
  y_cordi = randint(50, 150)
  speed = uniform (0.5, 1.5)   
  size = uniform (0.5,3)
  color = choice(colors)
  explosion_speed = uniform(0.2, 1)
  total_particles = randint(10,50)
  for i in range(1,total_particles):
   r = part(cv, idx = i, total = total_particles, explosion_speed = explosion_speed, x = x_cordi, y = y_cordi, 
    vx = speed, vy = speed, color=color, size = size, lifespan = uniform(0.6,1.75))
   (r)
  explode_points.append(objects)
 total_time = .0
 # keeps undate within a timeframe of 1.8 second
 while total_time < 1.8:
  sleep(0.01)
  tnew = time()
  t, dt = tnew, tnew - t
  for point in explode_points:
   for item in point:
    (dt)
  ()
  total_time += dt
 # recursive call to continue adding new explosion on canvas
 (wait_time, simulate, cv)
def close(*ignore):
 """Stops simulation loop and closes the window."""
 global root
 ()
 
if __name__ == '__main__':
 root = ()
 cv = (root, height=600, width=600)
 # use a nice background image
 image = ("./")#Background photo path of your choice, you can choose a cooler one, it will look #better!
 photo = (image)
 cv.create_image(0, 0, image=photo, anchor='nw')
 ()
 ("WM_DELETE_WINDOW", close)
 (100, simulate, cv)
 ()