LOGO-L> recursive curves

[Frank Caggiano <caggiano@atlantic.net>]

Sometimes the failures are more fun then the success's.  The following
code came about as I was looking for the sierpinski curve! Wasn't close,
but this does draw some interesting pictures.  I found the wreath and
star  buried in the code.  The wreath was run with the arguments:
'12 22000 120 6'  the star was run '6 2000 90 5'. 

The idea here is to divide the line segment by 5 instead of 3 as in the
Koch curve.

to fract :n :len :angle :level
	repeat :n [fractf :len :angle :level rt 360 / :n]
end

to fractf :len :angle :level
	if :level < 1 [fd :len stop]
	sepisf :len / 5 :angle :level - 1
	rt :angle
	sepisf :len / 5 :angle :level - 1
	lt 90
	sepisf :len / 5 :angle :level - 1
	lt 90
	sepisf :len / 5 :angle :level - 1
	rt :angle
	sepisf :len / 5 :angle :level - 1
end

There's lots more in there. Be warned the code does alot of backtraking
so while it may not look like anyting is going on before you stop it
check the status box to see if its really done (or better yet put a
'show "done' inst at the end of the main procedure).

:n is the number of 'sides', :len is the starting segment length, :angle
is the angle  between line segments and :level controls the recusion.

With high levels of recursion (and high here is really over 4) you need
large numbers for the :len parameter to really see anything. The :len is
being divided by 5 at each level of recursion.

This code is pretty much 'standard form' for these types of images.  The
idea for it came from Clayson's book, 'Visual Modeling with Logo'. (Gee
how I wish they would reissue it.)


regards
-- 
Frank Caggiano
caggiano@atlantic.net
http://www.atlantic.net/~caggiano