diff --git a/example/example.org b/example/example.org
index 5f90db8..716dcf2 100644
--- a/example/example.org
+++ b/example/example.org
@@ -1157,6 +1157,24 @@ tab
    [[file:dots/exampleQLHMVK.svg]]
    :end:
 
+   As usual, =dds= includes a specific function for constructing the
+   interaction graph of SBN.  This function does not include the
+   thresholds of the SBF in the interaction graph.
+
+   #+NAME: sbn-figure2-ig
+   #+BEGIN_SRC racket :results silent drawer :var sbn-figure2=munch-sexp(sbn-figure2)
+(dotit (sbn-interaction-graph (read-org-sbn sbn-figure2)))
+   #+END_SRC
+
+   #+BEGIN_SRC dot :file dots/exampleaSeyzw.svg :results raw drawer :cmd sfdp :noweb yes
+<<sbn-figure2-ig()>>
+   #+END_SRC
+
+   #+RESULTS:
+   :results:
+   [[file:dots/exampleaSeyzw.svg]]
+   :end:
+
 * Reaction systems
   :PROPERTIES:
   :header-args:racket: :prologue "#lang racket\n(require graph dds/rs dds/utils)"
diff --git a/networks.rkt b/networks.rkt
index 4f68fcb..14ab1b2 100644
--- a/networks.rkt
+++ b/networks.rkt
@@ -129,7 +129,8 @@
                                    (listof (listof (or/c number? symbol?))))]
                [tbn-interaction-graph (->* (tbn?) (#:zero-edges boolean?)
                                            graph?)]
-               [pretty-print-tbn-interaction-graph (-> graph? graph?)])
+               [pretty-print-tbn-interaction-graph (-> graph? graph?)]
+               [sbn-interaction-graph (-> sbn? graph?)])
  ;; Predicates
  (contract-out [variable? (-> any/c boolean?)]
                [state? (-> any/c boolean?)]
@@ -1677,3 +1678,25 @@
                             (b . ,(make-tbf/state '((a . -1)) -1)))))
     (check-equal? (graphviz (pretty-print-tbn-interaction-graph (tbn-interaction-graph tbn)))
                   "digraph G {\n\tnode0 [label=\"b:-1\"];\n\tnode1 [label=\"a:0\"];\n\tsubgraph U {\n\t\tedge [dir=none];\n\t\tnode0 -> node0 [label=\"0\"];\n\t\tnode1 -> node1 [label=\"0\"];\n\t}\n\tsubgraph D {\n\t\tnode0 -> node1 [label=\"1\"];\n\t\tnode1 -> node0 [label=\"-1\"];\n\t}\n}\n")))
+
+;;; Given an SBN, constructs its interaction graph.  As in
+;;; tbn-interaction-graph, the nodes of this graph are labeled with
+;;; the variable names, while the edges are labelled with the weights.
+;;;
+;;; If #:zero-edges is #t, the edges with zero weights will appear in
+;;; the interaction graph.
+(define (sbn-interaction-graph sbn
+                               #:zero-edges [zero-edges #t])
+  (update-graph (tbn-interaction-graph sbn)
+                #:v-func (match-lambda
+                           [(cons var _) var])))
+
+(module+ test
+  (test-case "sbn-interaction-graph"
+    (define sbn (hash
+                 'a
+                 (tbf/state (hash 'b 2) 0)
+                 'b
+                 (tbf/state (hash 'a 2) 0)))
+    (check-equal? (graphviz (sbn-interaction-graph sbn))
+                  "digraph G {\n\tnode0 [label=\"b\"];\n\tnode1 [label=\"a\"];\n\tsubgraph U {\n\t\tedge [dir=none];\n\t\tnode0 -> node1 [label=\"2\"];\n\t\tnode0 -> node0 [label=\"0\"];\n\t\tnode1 -> node1 [label=\"0\"];\n\t}\n\tsubgraph D {\n\t}\n}\n")))