diff --git a/networks.rkt b/networks.rkt
index 6d1ac3f..ce9401f 100644
--- a/networks.rkt
+++ b/networks.rkt
@@ -316,8 +316,8 @@
 (define (build-signed-interaction-graph network doms)
   (weighted-graph/directed
    (for*/fold ([edges '()])
-              ([(x  x-val) (in-hash network)]
-               [(y  y-val) (in-hash network)])
+              ([(x _) (in-hash network)]
+               [(y _) (in-hash network)])
      (match (get-interaction-sign network doms x y)
        ['0 edges]
        [sign (cons (list sign x y) edges)]))))