diff --git a/Language.agda b/Language.agda
index 7ece4ea..de86158 100644
--- a/Language.agda
+++ b/Language.agda
@@ -352,7 +352,7 @@ module Graphs where
         buildCfg (while _ repeat s) =
             (buildCfg s ⟨⊗⟩ pushEmptyBlock ⟨⊗⟩ pushEmptyBlock)
             update (λ { g ((idx₁ , idx₂) , idx , idx') →
-                      addEdges g ((idx , idx') ∷ (idx₂ , idx) ∷ []) })
+                      addEdges g ((idx , idx') ∷ (idx , idx₁) ∷ (idx₂ , idx) ∷ []) })
             map (λ { g ((idx₁ , idx₂) , idx , idx') → (idx , idx') })
 
 open import Lattice.MapSet _≟ˢ_