This map processing code is not working correctly for this image

I am doing map processing. In this task i have to draw the line vertical upwards(Brown color) when it touches another blob. At that time we have to replace the second blob centroid x value with starting blob x value and draw the skyblue line between two blobs We have to reapeat this process to all blob in the image.

In this image i get the perfect skyblue line from yellow rectangle to red circle. But this code work wrong from green circle to blue triangle

my code is below:

       for i=1:totalblob

  x=shape(i).cen(1,:);

  y=shape(i).cen(2,:);

          xi=x;  yi=y;

          w=0;flag=0;

  y=y-1;

    %TOP CHECKING

    for(trail=1:1000)

                 color_val=color(y,x,RGB);

                  RGB(y,x,1)=240;

                  RGB(y,x,2)=31;

                  RGB(y,x,3)=191;
                           
  if((color_val==shape(i).color)&w==0)
            if(y>5)
                          y=y-1;
                      end      %x=x-1;
                  else if (color_val==White)
              w=1;
              if(y>5)
                          y=y-1; 
                      end  %x=x-1;
            else if(color_val==Black)
                break;

                              else
                  for i=1:tblob
                    xa=shape(i).cen(1,:);
                    ya=shape(i).cen(2,:);
                     colorval=color(y,x,IMG);
                                      if (colorval==shape(i).color)
                                          if(x-40<xa<x+40)
                                              if(y-86<ya<y)
                                                  xj=xi; 
                                                  yj=ya;
                                                  shape(i).cen(1,:)=xi;
                                                  order(or).order=[xi,yi,xj,yj];
                                                  or=or+1;
                                                  RGB=line(xi,yi,xi,yj,RGB);   
                                                  flag=1;
                                                  xi=0;
                                                  yi=0;
                                                  xj=0;
                                                  yj=0;
                                                  break;
                                              end
                                          end
                                      end
                                  end
                              end
              end
            end
                  end
                 if (flag==1)
                   break;
                 end

              end
           imtool(RGB);   
  end

Answer 1

[Image Analyst]

Have you seen Steve's new blog entry on Maze solving? http://blogs.mathworks.com/steve/2014/01/21/solving-mazes-with-the-watershed-transform/