diff --git a/src/lib.rs b/src/lib.rs
index 18bd36e..0d0cff0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -193,8 +193,8 @@ impl State {
         State { lvl }
     }
 
-    fn toggle_box(&mut self, pos: Pos) {
-        self.lvl[pos] = if self.lvl[pos] == Cell::Goal(true) {
+    fn toggle_box(&mut self, pos: &Pos) {
+        self.lvl[*pos] = if self.lvl[*pos] == Cell::Goal(true) {
             Cell::Goal(false)
         } else {
             Cell::None
@@ -219,13 +219,13 @@ impl State {
 
                 match self.lvl[bpos] {
                     Cell::None => {
-                        self.toggle_box(dpos);
+                        self.toggle_box(&dpos);
                         self.lvl[bpos] = Cell::Box;
                         self.lvl.player = dpos;
                         return Ok((false, false));
                     }
                     Cell::Goal(false) => {
-                        self.toggle_box(dpos);
+                        self.toggle_box(&dpos);
                         self.lvl[bpos] = Cell::Goal(true);
                         self.lvl.player = dpos;
                         return Ok((true, false));