board backing referencing improvements

src/repr/coords.rs

@@ -20,9 +20,13 @@ impl CoordPair {
         Self(row * Board::BOARD_SIZE + col)
     }
 
-    fn from_index(&self) -> (CoordAxis, CoordAxis) {
+    fn into_indexes(&self) -> (CoordAxis, CoordAxis) {
         self.0.div_mod_floor(&Board::BOARD_SIZE)
     }
+
+    pub const fn area(pos: CoordAxis) -> Self {
+        Self(pos.pow(2) as CoordPairInner)
+    }
 }
 
 impl std::fmt::Display for CoordPair {
@@ -40,7 +44,7 @@ impl std::fmt::Debug for CoordPair {
 
 impl From<CoordPair> for (CoordAxis, CoordAxis) {
     fn from(val: CoordPair) -> Self {
-        val.from_index()
+        val.into_indexes()
     }
 }