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# examples derived from
# Visual Modeling with Logo: A Structural Approach to Seeing
# by James Clayson
# p. 146
# and
# Turtle Geometry: The Computer as a Medium for Exploring Mathematics
# by Harold Abelson and Andrea diSessa
# p. 91
# see http://physics.hallym.ac.kr/education/chaos/ncsa/Fgeom.html
# for some more explanation of fractals
from wrappers import CurvesTurtle
def draw(canvas):
t = CurvesTurtle(canvas)
t.cls()
t.pu()
t.lt(90)
t.fd(50)
t.rt(90)
t.pd()
# VM p. 146
t.fractalgon(3, 200, 4, -1)
t.fractalgon(3, 250, 4, 1)
# if you turn on the odometer you should see the total distance
# the turle has gone, so you can compare a level 1 curve to
# level 2, 3, etc.
# but you will need to subtract the radius (rad) distance * 2
# to compensate for the forward() and back() calls in fractalgon
# the same distance measurements can be done with other curves:
# cCurves, dragon, hilbert, or any drawing commands
# for example as the number of sides increases in a polygon
# the distance traveled will approach the 2 * pi * r (the radius)
# (circumference) of the circle bounded by the polygon
#
# odometer commands
# t.getOdometer()
# t.resumeOdometer()
# t.resetOdometer()
# t.suspendOdometer()
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