title: prolog out of local stack using lists
body: <p>i have to find route between two states and ive reached here and i am having error as of now regarding out of stack help me</p>
  
  <pre><code>% state 1 is border of state 2
  % borders(A , B). 
  borders(sasktchewan, alberta).
  borders(saskatchewan, manitoba).
  borders(saskatchewan, nwt).
  borders(alberta, british_columbia).
  borders(alberta, saskatchewan).
  borders(alberta, nwt).
  borders(british_coumbia, yukon).
  borders(british_coumbia, nwt).
  borders(british_coumbia, alberta).
  borders(nwt, saskatchewan).
  borders(nwt, alberta).
  borders(nwt, british_columbia).
  borders(nwt, yukon).
  borders(nwt, manitoba).
  borders(manitoba, saskatchewan).
  borders(manitoba, nwt).
  
  route( A, B, [ go(A,B) ] ) :-   borders( A, B ). 
  route( A, B, [ go(A,Z) | ZtoB ] ) :-   borders( A, Z ),   route( Z, B, ZtoB ).
  </code></pre>