draw a tree with python (via: http://preshing.com/20110920/the-python-with-statement-by-example)

draw-tree.py

import cairo
from contextlib import contextmanager
 
@contextmanager
def saved(cr):
    cr.save()
    try:
        yield cr
    finally:
        cr.restore()
 
def Tree(angle):
    cr.move_to(0, 0)
    cr.translate(0, -65)
    cr.line_to(0, 0)
    cr.stroke()
    cr.scale(0.72, 0.72)
    if angle > 0.12:
        for a in [-angle, angle]:
            with saved(cr):
                cr.rotate(a)
                Tree(angle * 0.75)
 
width  = 280
height = 204
 
surf = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
cr = cairo.Context(surf)
cr.set_source_rgb(1, 1, 1)
cr.rectangle(0, 0, width, height)
cr.fill()
cr.set_source_rgb(0, 0, 0)
cr.translate(140, 203)
cr.set_line_width(5)
Tree(0.75)
surf.write_to_png('fractal-tree.png')

tree-inverted.md

tree.md