public override void OnPaintSceneGUI(GridLayout grid, GameObject layer, BoundsInt position, GridBrushBase.Tool tool, bool executing)
    {
        LevelBrush.InitializeLevelCacheIfNecessary();
        var invalidFloors = LevelBrush.GetAllInvalidFloors();

        BrushEditorUtility.BeginQuads(new Color(1f, 0f, 0f, 0.5f));
        foreach (var pos in invalidFloors)
        {
            BrushEditorUtility.DrawQuadBatched(grid, pos);
        }
        BrushEditorUtility.EndQuads();

        base.OnPaintSceneGUI(grid, layer, position, tool, executing);
    }