diff --git a/board/src/piece_sets/mailbox.rs b/board/src/piece_sets/mailbox.rs
index ce11cf0..4fc9ec4 100644
--- a/board/src/piece_sets/mailbox.rs
+++ b/board/src/piece_sets/mailbox.rs
@@ -48,22 +48,20 @@ impl From<[Option<Piece>; Square::NUM]> for Mailbox {
 
 impl FromIterator<PlacedPiece> for Mailbox {
     fn from_iter<T: IntoIterator<Item = PlacedPiece>>(iter: T) -> Self {
-        let mut mailbox = Self::new();
-        for placed_piece in iter {
-            mailbox.set(placed_piece.piece(), placed_piece.square());
-        }
-
-        mailbox
+        iter.into_iter()
+            .fold(Self::new(), |mut mailbox, placed_piece| {
+                mailbox.set(placed_piece.piece(), placed_piece.square());
+                mailbox
+            })
     }
 }
 
 impl FromIterator<(Square, Piece)> for Mailbox {
     fn from_iter<T: IntoIterator<Item = (Square, Piece)>>(iter: T) -> Self {
-        let mut mailbox = Self::new();
-        for (square, piece) in iter {
-            mailbox.set(piece, square);
-        }
-
-        mailbox
+        iter.into_iter()
+            .fold(Self::new(), |mut mailbox, (square, piece)| {
+                mailbox.set(piece, square);
+                mailbox
+            })
     }
 }