---
diff --git a/week4.mdwn b/week4.mdwn
index e1dcc4e9..83d54df1 100644
--- a/week4.mdwn
+++ b/week4.mdwn
@@ -27,10 +27,10 @@ A: Right:
```
let Y = \T. (\x. T (x x)) (\x. T (x x)) in
Y Y ≡ \T. (\x. T (x x)) (\x. T (x x)) Y
- ~~> (\x. Y (x x)) (\x. Y (x x))
- ~~> Y ((\x. Y (x x)) (\x. Y (x x)))
- ~~> Y (Y ((\x. Y (x x)) (\x. Y (x x))))
- ~~> Y (Y (Y (...(Y (Y Y))...)))
```

+~~> (\x. Y (x x)) (\x. Y (x x))
+~~> Y ((\x. Y (x x)) (\x. Y (x x)))
+~~> Y (Y ((\x. Y (x x)) (\x. Y (x x))))
+~~> Y (Y (Y (...(Y (Y Y))...)))
#Q: Ouch! Stop hurting my brain.#
@@ -49,9 +49,9 @@ successor. Let's just check that `X = succ X`:
```
let succ = \n s z. s (n s z) in
let X = (\x. succ (x x)) (\x. succ (x x)) in
succ X
- ≡ succ ( (\x. succ (x x)) (\x. succ (x x)) )
- ~~> succ (succ ( (\x. succ (x x)) (\x. succ (x x))))
- ≡ succ (succ X)
```

+≡ succ ( (\x. succ (x x)) (\x. succ (x x)) )
+~~> succ (succ ( (\x. succ (x x)) (\x. succ (x x))))
+≡ succ (succ X)
You should see the close similarity with `Y Y` here.