%%%%%%%%%%%%%%%%%%%%% Word driven tesselation  %%%%%%%%%%%%%%%%%%%
%
% PTESS
% Usage: PTESS(P0,word,ti,drawIP)
%
% Inputs:  P0 initial polygon
%          word   - the sequence of reflections to drive the tesellation 
%          ti     - title of tesselation
%          drawIP - draw initial polygon
%
%          the sequence of reflections given by word are used to tile 
%          the disc with the reflections of P0

function T = ptess(P0,word,ti,drawIP)

% initializations
I = sqrt(-1);  
P = P0;

if (nargin >= 4)
     DIP = drawIP;
    else 
     DIP = 1;
   end; 
   
   
boundary(ti,'','w'); 
if DIP plotpoly(P,'w'); end;   

word = word(:);
n = length(word);
for i = 1:n
    side = word(i);
    P2 = polyrefl(P, side);
    if (side >= 'a') plotpoly(P2,'w'); end;
        P = P2;
    end;