diff --git a/book/src/chapter_2.md b/book/src/chapter_2.md
index 97b956df..248ce47a 100644
--- a/book/src/chapter_2.md
+++ b/book/src/chapter_2.md
@@ -547,9 +547,9 @@ Now we implement a new function, `try_move_player`:
 ```rust
 fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     let mut positions = ecs.write_storage::<Position>();
-    let mut players = ecs.write_storage::<Player>();
+    let players = ecs.read_storage::<Player>();
 
-    for (_player, pos) in (&mut players, &mut positions).join() {
+    for (_player, pos) in (&players, &mut positions).join() {
         pos.x = min(79 , max(0, pos.x + delta_x));
         pos.y = min(49, max(0, pos.y + delta_y));
     }
@@ -561,7 +561,7 @@ Drawing on our previous experience, we can see that this gains write access to `
 We'll add a second function to read the keyboard information provided by RLTK:
 
 ```rust
-fn player_input(gs: &mut State, ctx: &mut Rltk) {
+fn player_input(gs: &mut State, ctx: &Rltk) {
     // Player movement
     match ctx.key {
         None => {} // Nothing happened
diff --git a/chapter-02-helloecs/src/main.rs b/chapter-02-helloecs/src/main.rs
index 6d036183..0743eaba 100644
--- a/chapter-02-helloecs/src/main.rs
+++ b/chapter-02-helloecs/src/main.rs
@@ -28,15 +28,15 @@ struct State {
 
 fn try_move_player(delta_x: i32, delta_y: i32, ecs: &mut World) {
     let mut positions = ecs.write_storage::<Position>();
-    let mut players = ecs.write_storage::<Player>();
+    let players = ecs.read_storage::<Player>();
 
-    for (_player, pos) in (&mut players, &mut positions).join() {
+    for (_player, pos) in (&players, &mut positions).join() {
         pos.x = min(79 , max(0, pos.x + delta_x));
         pos.y = min(49, max(0, pos.y + delta_y));
     }
 }
 
-fn player_input(gs: &mut State, ctx: &mut Rltk) {
+fn player_input(gs: &mut State, ctx: &Rltk) {
     // Player movement
     match ctx.key {
         None => {} // Nothing happened