%
% triangle_recursive.m Demonstrating the recursion and
% graphics interaction
%
function triangle_recursive(level,a,b,len,factor)
%

%
%
  x(1)=a;
  x(2)=x(1)+len;
  x(3)=x(2)-len/2; % should be 2 not factor.
  x(4)=x(1);
  %--------------------
  y(1)=b;
  y(2)=y(1);
  y(3)=y(2)+len*sin(pi/3);
  y(4)=y(1);
%

 for i=1:3   
    line([x(i) x(i+1)],[y(i) y(i+1)]);
    if(level==1)
      % text(x(i),y(i),num2str(i));
    end
 end % i
 %
 for i=1:level
    len_small=len/(factor*1.0);
    triangle_recursive(level-1,x(1),y(1),len_small,factor);
    triangle_recursive(level-1,x(2)-len_small,y(2),len_small,factor);
    
    xt=x(3)-(len_small*cos(pi/3));
    yt=y(3)-(len_small*sin(pi/3));
    triangle_recursive(level-1,xt,yt,len_small,factor);
 end