def d(n,x,l,t):y=x[0]+l*math.sin(t),x[1]+l*math.cos(t);r=random.random;\
draw.line(c,(a[u]+a[u+1]*n,a[u+2]+a[u+3]*n,a[u+4]),x,y);display.flip();\
event.poll();n and[d(n-1,y,l*(.7+r()/5),t+i*r())for i in(-1,1)];20050317
from pygame import*;import math,random,time;c=display.set_mode((800,600)
);u=time.localtime()[1]%12/3*5;s='winter','spring','summer','autumn';a=(
80,4,80,2,80,120,2,120,-2,60,60,3,180,-5,60,180,0,180,-6,60);p=math.pi+0
while 1:c.fill((0,0,16));display.set_caption("tree: "+s[u/5]);draw.rect(
c,(32,)*3,(0,550,800,50));d(17,(400,550),100,p);u=(u+5)%20;time.sleep(3)