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From: jones@pyrite.cs.uiowa.edu (Douglas W. Jones,201H
 MLH,3193350740,3193382879)
Newsgroups: rec.arts.ascii,alt.ascii-art,alt.binaries.pictures.ascii
Subject: Re: LINE - Hilbert curves
Date: 8 Jun 1994 11:31:57 -0500
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Those hilbert curves were really messed up in transmission over the net!
The problem is that a leading period gets translated to two leading
periods to defeat something somewhere, and the result was hash.  Never
start a line with a dot if you want your ASCII ART to survive the net!

Here is a corrected version of my posting:

I wrote an image processing program some time ago to explore the effect
of replacing raster scanning with Hilbert curve scanning, and a side
effect of this work was a little program that generates hilbert curves:

 % filltest 2 2
 ._.
 ._!
 %
 % filltest 4 4
 . ._._.
 !_! ._!
 ._. !_.
 ! !_._!
 %
 % filltest 8 8
 ._. ._._. ._._.
 ._! !_. !_! ._!
 ! ._. ! ._. !_.
 !_! !_! ! !_._!
 ._. ._. ! ._._.
 ! !_! ! !_! ._!
 !_. ._! ._. !_.
 ._! !_._! !_._!
 %
 % filltest 16 16
 . ._._. ._._. ._._. ._._. ._._.
 !_! ._! !_. !_! ._! !_. !_! ._!
 ._. !_. ._! ._. ! ._. ! ._. !_.
 ! !_._! !_._! ! !_! !_! ! !_._!
 !_. ._._._. ._! ._. ._. ! ._._.
 ._! !_. ._! !_. ! !_! ! !_! ._!
 ! ._. ! ! ._. ! !_. ._! ._. !_.
 !_! !_! !_! !_! ._! !_._! !_._!
 ._. ._. ._. ._. !_. ._._. ._._.
 ! !_! ! ! !_! ! ._! !_. !_! ._!
 !_. ._! !_. ._! ! ._. ! ._. !_.
 ._! !_._._! !_. !_! !_! ! !_._!
 ! ._._. ._._. ! ._. ._. ! ._._.
 !_! ._! !_. !_! ! !_! ! !_! ._!
 ._. !_. ._! ._. !_. ._! ._. !_.
 ! !_._! !_._! !_._! !_._! !_._!
 %
 % filltest 32 32
 ._. ._._. ._._. ._._. ._._. ._._. ._._. ._._. ._._. ._._. ._._.
 ._! !_. !_! ._! !_. !_! ._! !_. !_! ._! !_. !_! ._! !_. !_! ._!
 ! ._. ! ._. !_. ._! ._. ! ._. ! ._. !_. ._! ._. ! ._. ! ._. !_.
 !_! !_! ! !_._! !_._! ! !_! !_! ! !_._! !_._! ! !_! !_! ! !_._!
 ._. ._. ! ._._. ._._. ! ._. ._. !_. ._._._. ._! ._. ._. ! ._._.
 ! !_! ! !_! ._! !_. !_! ! !_! ! ._! !_. ._! !_. ! !_! ! !_! ._!
 !_. ._! ._. !_. ._! ._. !_. ._! ! ._. ! ! ._. ! !_. ._! ._. !_.
 ._! !_._! !_._! !_._! !_._! !_. !_! !_! !_! !_! ._! !_._! !_._!
 ! ._._. ._._. ._. ._._. ._._. ! ._. ._. ._. ._. !_. ._._. ._._.
 !_! ._! !_. !_! !_! ._! !_. !_! ! !_! ! ! !_! ! ._! !_. !_! ._!
 ._. !_. ._! ._. ._. !_. ._! ._. !_. ._! !_. ._! ! ._. ! ._. !_.
 ! !_._! !_._! ! ! !_._! !_._! ! ._! !_._._! !_. !_! !_! ! !_._!
 !_. ._._._. ._! !_. ._._._. ._! ! ._._. ._._. ! ._. ._. ! ._._.
 ._! !_. ._! !_. ._! !_. ._! !_. !_! ._! !_. !_! ! !_! ! !_! ._!
 ! ._. ! ! ._. ! ! ._. ! ! ._. ! ._. !_. ._! ._. !_. ._! ._. !_.
 !_! !_! !_! !_! !_! !_! !_! !_! ! !_._! !_._! !_._! !_._! !_._!
 ._. ._. ._. ._. ._. ._. ._. ._. ! ._._. ._._. ._._. ._._. ._._.
 ! !_! ! ! !_! ! ! !_! ! ! !_! ! !_! ._! !_. !_! ._! !_. !_! ._!
 !_. ._! !_. ._! !_. ._! !_. ._! ._. !_. ._! ._. ! ._. ! ._. !_.
 ._! !_._._! !_. ._! !_._._! !_. ! !_._! !_._! ! !_! !_! ! !_._!
 ! ._._. ._._. ! ! ._._. ._._. ! !_. ._._._. ._! ._. ._. ! ._._.
 !_! ._! !_. !_! !_! ._! !_. !_! ._! !_. ._! !_. ! !_! ! !_! ._!
 ._. !_. ._! ._. ._. !_. ._! ._. ! ._. ! ! ._. ! !_. ._! ._. !_.
 ! !_._! !_._! !_! !_._! !_._! ! !_! !_! !_! !_! ._! !_._! !_._!
 !_. ._._. ._._. ._._. ._._. ._! ._. ._. ._. ._. !_. ._._. ._._.
 ._! !_. !_! ._! !_. !_! ._! !_. ! !_! ! ! !_! ! ._! !_. !_! ._!
 ! ._. ! ._. !_. ._! ._. ! ._. ! !_. ._! !_. ._! ! ._. ! ._. !_.
 !_! !_! ! !_._! !_._! ! !_! !_! ._! !_._._! !_. !_! !_! ! !_._!
 ._. ._. ! ._._. ._._. ! ._. ._. ! ._._. ._._. ! ._. ._. ! ._._.
 ! !_! ! !_! ._! !_. !_! ! !_! ! !_! ._! !_. !_! ! !_! ! !_! ._!
 !_. ._! ._. !_. ._! ._. !_. ._! ._. !_. ._! ._. !_. ._! ._. !_.
 ._! !_._! !_._! !_._! !_._! !_._! !_._! !_._! !_._! !_._! !_._!
 %
 % filltest 19 9
 ._. ._._. ._._. ._._. ._._. ._._. ._.
 ._! !_. !_! ._! !_. !_! ._! !_. !_! !
 ! ._. ! ._. !_. ._! ._. ! ._. ! ._. !
 !_! !_! ! !_._! !_._! ! !_! !_! ! !_!
 ._. ._. ! ._._. ._._. ! ._. ._. !_. .
 ! !_! ! !_! ._! !_. !_! ! !_! ! ._! !
 !_. ._! ._. !_. ._! ._. !_. ._! ! ._.
 ._! !_._! !_._! !_._! !_._! !_. !_! !
 !_._._._._._._._._._._._._._._! ._._.
 %
The final example above shows that the program does some odd things
when you ask it to fill a region that isn't a power-of-two square,
but what it does, in that case, didn't matter in the least for my
data compression application.

				Doug Jones
 				jones@cs.uiowa.edu