        }
    }
    
    /**
     Draw a half transparent piece at the coordinate that the mouse is hovering over
     */
    private func drawPendingPiece() {
        if let co = pendingPieceCo {
            if !isValid(co, dim) { return }
            if pieces[co.row][co.col] == .none { // If the coordinate is not occupied
                let rect = self.rect(at: co)
                if board.curPlayer == .black {
                    blackWithAlpha?.draw(in: rect)
                } else {