(let ((graph (make-container 'graph-container)))
(loop for (a b) in '((r s) (r v) (s w) (t u) (t w) (t x)
(u y) (w x) (x y)) do
(let ((graph (make-container 'graph-container)))
(loop for (a b) in '((r s) (r v) (s w) (t u) (t w) (t x)
(u y) (w x) (x y)) do