tex 4 is it's own strong component, and vertices 7,8,9 are in another
% one.  Remember that a strong component is all the vertices mutually
% reachable from a given vertex.  If you start at vertex 4, you can't get
% anywhere else!  That's why it is in a different component than vertices 
% 1,2,3,5,6.

%%
% We also have a largest_component function that makes it easy to just get
% the largest connected component.
clf;
[Acc,f] = largest_component(A);
graph_draw(Acc,xy(f,:)) 
%%
% The filter variable f, tells 