function out=catt(A,cc)
%
% CATT(A,cc). A is a 2x2 real matrix. cc is a (1,3)-color vecor.
% SELFDEMONSTRATING whne called w/o paramters.
%
% Visualizing linear transformations of the plane by their
% effects on a cat's face. Good ewxample for block-multipli-
% cation of matrices: Each column is one vertex!
% An older file cat.m has been retired due to name conflicts.
% Revised Dec.12, 1996: Documentation added April 1999.
% Revisions: April 1999 documentation added.
%            July 1999: Added axis-equal, initial clf
% All rights reserved. Matt Kawski. http://math.la.asu.edu/~kawski

% Define the vertices for the face.
%
clf
axis equal
format short
topx=[1 .98 .8  .83 .8  .77  .5 .25 0 -.25 -.5 -.8 -.8 -.98 -1];
topy=[0 .15 .7 1.15 1.03 1.15 .85 .95 1  .95 .85 1.2  .7  .15  0];
botx=-cos(pi*[1:10]/10);
boty=-sin(pi*[1:10]/10);
wiskx=[.2 1.3 .2 1.4 .2 1.4 .2 1.3 .2 .17 .13 .08 .03 0];
wisky=[ 0  .3  0  .1  0 -.1  0 -.3  0  .1 -.1 .1  -.1 0]-.2;
xeye=[0  .2  .3 .4 .43 .45 .43 .4 .37 .35 .37 .4  .5 .6 .5  .4 .3  .2  0];
yeye=[.5 .5 .43 .4 .42 .5  .58 .6 .58 .5  .42 .4  .43 .5 .57 .6 .57 .5 .5]-.2;
x=[topx,botx,wiskx,xeye,-xeye,fliplr(-wiskx)];
y=[topy,boty,wisky,yeye, yeye,fliplr(wisky)];
%
% Draw the original face.
%
fill(x,y,[0,.3,1])
plot(x,y,'m-')
%
pts=[x;y];
%
% Apply the linear transformation. If none given use random
% 2x2 matrix with INTEGER VALUES (quite often singular!)
%
if nargin < 1
   A=floor(5*rand(2,2)-2)
   end
Apts=A*pts;
%
% Overlay the transformewd image.
%
xnew=Apts(1,:);
ynew=Apts(2,:);
axis(5*[-1,1,-1,1])
hold on
if nargin < 2
   cc=rand(1,3)
   end
fill(xnew,ynew,cc)
%
% Replot the original face as it may have been covered up.
%
plot(x,y,'m-')