diff --git a/src/exercises/day_9.ts b/src/exercises/day_9.ts
index 18c69b4..e347064 100644
--- a/src/exercises/day_9.ts
+++ b/src/exercises/day_9.ts
@@ -98,90 +98,79 @@ function is_area_red_green(
   // Error 1: 4560365591
   // Error 2: 248032161
   // Error 3: 4638219675
-  // NOTE: I do not need to verify every wall, just the opposite corners
-  // Verify left wall
-  const ls_cover = floor.red_tiles.some((tile) => {
-    return (tile.x === tl_corner.x && tile.y <= tl_corner.y &&
-      ((floor.red_tiles.some((tile_2) =>
-        tile_2.x === tile.x && tile_2.y >= bl_corner.y
-      )) || (floor.red_tiles.some((tile_3) =>
-        tile_3.x <= tile.x && tile_3.y >= bl_corner.y &&
-        floor.red_tiles.some((tile_4) =>
-          tile_3.x <= tile_4.x && tile_3.y === tile_4.y
-        )
-      )))) ||
-      (tile.x === bl_corner.x && tile.y <= bl_corner.y &&
-        ((floor.red_tiles.some((tile_2) =>
-          tile_2.x === tile.x && tile_2.y <= tl_corner.y
-        )) || (floor.red_tiles.some((tile_3) =>
-          tile_3.x <= tile.x && tile_3.y <= tl_corner.y &&
-          floor.red_tiles.some((tile_4) =>
-            tile_3.x <= tile_4.x && tile_3.y === tile_4.y
-          )
-        )))); // NOTE: should also compare with opposite situation (first side and then point or 2 sides)
-  });
-  const rs_cover = floor.red_tiles.some((tile) => {
-    return (tile.x === tr_corner.x && tile.y <= tr_corner.y &&
-      ((floor.red_tiles.some((tile_2) =>
-        tile_2.x === tile.x && tile_2.y >= br_corner.y
-      )) || (floor.red_tiles.some((tile_3) =>
-        tile_3.x <= tile.x && tile_3.y >= br_corner.y &&
-        floor.red_tiles.some((tile_4) =>
-          tile_3.x <= tile_4.x && tile_3.y === tile_4.y
-        )
-      )))) ||
-      (tile.x === br_corner.x && tile.y >= br_corner.y &&
-        ((floor.red_tiles.some((tile_2) =>
-          tile_2.x === tile.x && tile_2.y <= tr_corner.y
-        )) || (floor.red_tiles.some((tile_3) =>
-          tile_3.x <= tile.x && tile_3.y <= tr_corner.y &&
-          floor.red_tiles.some((tile_4) =>
-            tile_3.x <= tile_4.x && tile_3.y === tile_4.y
-          )
-        )))); // NOTE: should also compare with opposite situation (first side and then point)
-  });
-  const ts_cover = floor.red_tiles.some((tile) => {
-    return (tile.x <= tl_corner.x && tile.y === tr_corner.y &&
-      ((floor.red_tiles.some((tile_2) =>
-        tile_2.x >= tr_corner.x && tile_2.y === tile.y
-      )) || (floor.red_tiles.some((tile_3) =>
-        tile_3.x >= tile.x && tile_3.y <= tr_corner.y &&
-        floor.red_tiles.some((tile_4) =>
-          tile_3.x === tile_4.x && tile_3.y >= tile_4.y
-        )
-      )))) ||
-      (tile.x >= bl_corner.x && tile.y === br_corner.y &&
-        ((floor.red_tiles.some((tile_2) =>
-          tile_2.x <= br_corner.x && tile_2.y === tile.y
-        )) || (floor.red_tiles.some((tile_3) =>
-          tile_3.x >= tile.x && tile_3.y >= br_corner.y &&
-          floor.red_tiles.some((tile_4) =>
-            tile_3.x === tile_4.x && tile_3.y >= tile_4.y
-          )
-        )))); // NOTE: should also compare with opposite situation (first side and then point)
-  });
-  const bs_cover = floor.red_tiles.some((tile) => {
-    return (tile.x <= bl_corner.x && tile.y === bl_corner.y &&
-      ((floor.red_tiles.some((tile_2) =>
-        tile_2.x >= tr_corner.x && tile_2.y === tile.y
-      )) || (floor.red_tiles.some((tile_3) =>
-        tile_3.x >= tile.x && tile_3.y >= br_corner.y &&
-        floor.red_tiles.some((tile_4) =>
-          tile_3.x === tile_4.x && tile_3.y <= tile_4.y
-        )
-      )))) ||
-      (tile.x >= tr_corner.x && tile.y === tr_corner.y &&
-        ((floor.red_tiles.some((tile_2) =>
-          tile_2.x <= tl_corner.x && tile_2.y === tile.y
-        )) || (floor.red_tiles.some((tile_3) =>
-          tile_3.x >= tile.x && tile_3.y <= tr_corner.y &&
-          floor.red_tiles.some((tile_4) =>
-            tile_3.x === tile_4.x && tile_3.y <= tile_4.y
-          )
-        )))); // NOTE: should also compare with opposite situation (first side and then point)
-  });
+  const { red_tiles: tiles } = floor;
 
-  return ls_cover && rs_cover && ts_cover && bs_cover;
+  let first_verify = false;
+  if (
+    tl_corner.x === a.x && tl_corner.y === a.y ||
+    tl_corner.x === b.x && tl_corner.y === b.y
+  ) {
+    first_verify = tiles.some((tile) =>
+      tile.x === tl_corner.x && tile.y >= max_y ||
+      tile.x <= min_x && tile.y === max_y
+    ) || tiles.some((tile) =>
+      tile.x <= min_x && tile.y <= max_y && tiles.some((tile_2) =>
+        tile_2.y >= max_y && tile_2.x === tile.x
+      )
+    ) || tiles.some((tile) =>
+      tile.y >= max_y && tile.x <= min_x && tiles.some((tile_2) =>
+        tile_2.x >= min_x && tile_2.y === tile.y
+      )
+    );
+  } else if (
+    tr_corner.x === a.x && tr_corner.y === a.y ||
+    tr_corner.x === b.x && tr_corner.y === b.y
+  ) {
+    first_verify = tiles.some((tile) =>
+      tile.x === tr_corner.x && tile.y >= max_y ||
+      tile.x >= max_x && tile.y === max_y
+    ) || tiles.some((tile) =>
+      tile.x >= max_x && tile.y <= max_y && tiles.some((tile_2) =>
+        tile_2.y >= max_y && tile_2.x === tile.x
+      )
+    ) || tiles.some((tile) =>
+      tile.y >= max_y && tile.x >= max_x && tiles.some((tile_2) =>
+        tile_2.x <= min_x && tile_2.y === tile.y
+      )
+    );
+  }
+
+  let second_verify = false;
+  if (
+    bl_corner.x === a.x && bl_corner.y === a.y ||
+    bl_corner.x === b.x && bl_corner.y === b.y
+  ) {
+    second_verify = tiles.some((tile) =>
+      tile.x === min_x && tile.y <= min_y ||
+      tile.x <= min_x && tile.y === min_y
+    ) || tiles.some((tile) =>
+      tile.x <= min_x && tile.y <= min_y && tiles.some((tile_2) =>
+        tile_2.y >= min_y && tile_2.x === tile.x
+      )
+    ) || tiles.some((tile) =>
+      tile.y <= min_y && tile.x <= min_x && tiles.some((tile_2) =>
+        tile_2.x >= min_x && tile_2.y === tile.y
+      )
+    );
+  } else if (
+    br_corner.x === a.x && br_corner.y === a.y ||
+    br_corner.x === b.x && br_corner.y === b.y
+  ) {
+    second_verify = tiles.some((tile) =>
+      tile.x === tr_corner.x && tile.y <= min_y ||
+      tile.x >= max_x && tile.y === min_y
+    ) || tiles.some((tile) =>
+      tile.x >= max_x && tile.y <= min_y && tiles.some((tile_2) =>
+        tile_2.y >= min_y && tile_2.x === tile.x
+      )
+    ) || tiles.some((tile) =>
+      tile.y <= min_y && tile.x <= max_x && tiles.some((tile_2) =>
+        tile_2.x >= max_x && tile_2.y === tile.y
+      )
+    );
+  }
+
+  return first_verify && second_verify;
 }
 
 function calc_distance(a: Coordinate, b: Coordinate): number {