func (f *Field) AbsorbPiece(piece *Piece, x, y int, angle Angle) {
	piece.AbsorbInto(f, x, y, angle)
	if f.flushable() {
		f.flushCount = maxFlushCount
	}
}
func (f *Field) AbsorbPiece(piece *Piece, x, y int, angle Angle) {
	piece.AbsorbInto(f, x, y, angle)
	if f.flushable() {
		f.flushCount = maxFlushCount
	}
}
// AbsorbPiece absorbs the piece at (x, y) with the given angle into the field.