%%%%%%%%%%%%%%%%%%%%% Word driven quadilateral tesselation  %%%%%%%%%%%%%%%%%%%
%
% QTESS
% Usage: QTESS(r,s,t,u,h,word,ti,drawIQ,Q0)
%
% Inputs:  r,s,t,u,h same inputs as qmtess
%          Q0 -     optional initial quadrilateral
%          word   - the sequence of reflections to drive the tesellation 
%          ti     - title of tesselation
%          drawIQ - draw initial quadrilateral
%
%          the sequence of reflections given by word are used to tile 
%          the disc with the reflections of Q0

function Q = qtess(r,s,t,u,h,word,ti,drawIQ,Q0)

% initializations
I = sqrt(-1);  
if (nargin >= 8)
     DIQ = drawIQ;
    else 
     DIQ = 1;
   end; 

if (nargin >= 9)
     Q = Q0;
    else 
     Q = qschwartz1(r,s,t,u,h);
   end; 

   
   
boundary(ti,'','w'); 
if DIQ plotpoly(Q,'w'); end;   

word = word(:);
n = length(word);
for i = 1:n
    side = word(i);
    Q2 = polyrefl(Q, side);
    if (side >= 'a') plotpoly(Q2,'w'); end;
        Q = Q2;
    end;