diff --git a/src/repr/pos_map.rs b/src/repr/pos_map.rs
index 6a2719f..be89972 100644
--- a/src/repr/pos_map.rs
+++ b/src/repr/pos_map.rs
@@ -14,12 +14,12 @@ impl<T: Copy> PosMap<T> {
         Self(MaybeUninit::zeroed().assume_init())
     }
 
-    pub const fn from(v: [[T; Board::SIZE as usize]; Board::SIZE as usize]) -> Self {
+    pub const fn from(mut v: [[T; Board::SIZE as usize]; Board::SIZE as usize]) -> Self {
         let mut n = unsafe { Self::uninit() };
 
         const_for!(i in 0..Board::SIZE => {
             const_for!(j in 0..Board::SIZE => {
-                n.set(CoordPair::from_axes(i, j), v[i as usize][j as usize]);
+                std::mem::swap(n.get_mut(CoordPair::from_axes(i, j)), &mut v[i as usize][j as usize]);
             });
         });
         n