public List <Vector2Int> AttacksForPiece(GameObject pieceObject)
{
Piece piece = pieceObject.GetComponent <Piece>();
Vector2Int gridPoint = GridForPiece(pieceObject);
var locations = piece.AttackLocations(gridPoint);
// rules that are true for any piece!
// get rid if off board
locations.RemoveAll(tile => tile.x < 0 || tile.x > 7 ||
tile.y < 0 || tile.y > 7);
// filter out locations without a piece
locations.RemoveAll(tile => !PieceAtGrid(tile));
locations.RemoveAll(tile => FriendlyPieceAt(tile));
return(locations);
}