diff --git a/src/HottBook/Chapter2.lagda.md b/src/HottBook/Chapter2.lagda.md
index 60d1810..2d2833a 100644
--- a/src/HottBook/Chapter2.lagda.md
+++ b/src/HottBook/Chapter2.lagda.md
@@ -307,7 +307,9 @@ idToEquiv {A} {B} p = func , equiv
     func-inv b = transport id (sym p) b
 
     homotopy : (func ∘ func-inv) ∼ id
-    homotopy x = {!  !}
+    homotopy x = 
+      let wtf = transport id (sym p) (transport id p x) in
+      {!  !}
 
     equiv = record
       { g = func-inv