Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!texbell!chinacat!woody
From: woody@chinacat.Unicom.COM (Woody Baker @ Eagle Signal)
Newsgroups: comp.lang.postscript
Subject: Re: Optical Illusion
Summary: optical
Message-ID: <1144@chinacat.Unicom.COM>
Date: 10 Apr 90 00:06:15 GMT
References: <1034@cnca.cnca-cam.fr>
Organization: a guest of Unicom Systems Development, Austin
Lines: 70

Here is a cute little bit of PS that I cooked up the other day.
Postscript lends itself well to drawing optical illusions.  How about
y'all posting some.  Does anyone have any Escher? (sic)
Somewhere, I have seen an impossible nut.  I can't find a copy of it (it
was just a drawing).  It was shown in an exploded diagram for the 3
pronged impossible "fork".
Cheers
Woody


%
% Optical illusion
% written by Woody Baker
% Rt.1 Box I
% Manor, Tx. 78653
%
% hereby placed in the public domain.  Would appreciate the header
% remaining in-tact.
%

%
% do 1/4th of the drawing
%
/onequarter
	{
	60 160 moveto
	20 160 lineto
	20 80 lineto
	160 80 lineto
	60 180 moveto
	0 180 lineto
	0 60 lineto
	160 60 lineto
	40 160 moveto
	40 100 lineto
	160 100 lineto
	60 200 moveto
	20 200 lineto
	0 180 lineto
	40 100 moveto
	20 80 lineto
	} def
%
% draw the illusion and label it
%	
/optical
	{	
	0 0 moveto onequarter
	gsave
	-90 rotate -260 0 translate onequarter
	-90 rotate -260 0 translate onequarter
	-90 rotate -260 0 translate onequarter
	stroke
	grestore
	/Helvetica findfont 20 scalefont setfont
	-10 -25 moveto
	(Brought to you By Woody Baker) show
	} def
%
% application code.  Positions and scales and draws the actual
% illusion.
%	
/xcoord 140 def
/ycoord 240 def	
gsave	
xcoord ycoord translate
1 1 scale
optical
grestore
showpage