Staging
v0.5.1
v0.5.1
https://github.com/python/cpython
Tip revision: fdbdcfe020f8b55a1893d1185d7a250bce12625e authored by Benjamin Peterson on 30 June 2014, 01:58:16 UTC
bump to 2.7.8
bump to 2.7.8
Tip revision: fdbdcfe
tdemo_lindenmayer_indian.py
#!/usr/bin/env python
""" turtle-example-suite:
xtx_lindenmayer_indian.py
Each morning women in Tamil Nadu, in southern
India, place designs, created by using rice
flour and known as kolam on the thresholds of
their homes.
These can be described by Lindenmayer systems,
which can easily be implemented with turtle
graphics and Python.
Two examples are shown here:
(1) the snake kolam
(2) anklets of Krishna
Taken from Marcia Ascher: Mathematics
Elsewhere, An Exploration of Ideas Across
Cultures
"""
################################
# Mini Lindenmayer tool
###############################
from turtle import *
def replace( seq, replacementRules, n ):
for i in range(n):
newseq = ""
for element in seq:
newseq = newseq + replacementRules.get(element,element)
seq = newseq
return seq
def draw( commands, rules ):
for b in commands:
try:
rules[b]()
except TypeError:
try:
draw(rules[b], rules)
except:
pass
def main():
################################
# Example 1: Snake kolam
################################
def r():
right(45)
def l():
left(45)
def f():
forward(7.5)
snake_rules = {"-":r, "+":l, "f":f, "b":"f+f+f--f--f+f+f"}
snake_replacementRules = {"b": "b+f+b--f--b+f+b"}
snake_start = "b--f--b--f"
drawing = replace(snake_start, snake_replacementRules, 3)
reset()
speed(3)
tracer(1,0)
ht()
up()
backward(195)
down()
draw(drawing, snake_rules)
from time import sleep
sleep(3)
################################
# Example 2: Anklets of Krishna
################################
def A():
color("red")
circle(10,90)
def B():
from math import sqrt
color("black")
l = 5/sqrt(2)
forward(l)
circle(l, 270)
forward(l)
def F():
color("green")
forward(10)
krishna_rules = {"a":A, "b":B, "f":F}
krishna_replacementRules = {"a" : "afbfa", "b" : "afbfbfbfa" }
krishna_start = "fbfbfbfb"
reset()
speed(0)
tracer(3,0)
ht()
left(45)
drawing = replace(krishna_start, krishna_replacementRules, 3)
draw(drawing, krishna_rules)
tracer(1)
return "Done!"
if __name__=='__main__':
msg = main()
print msg
mainloop()