examples/2048/2048/tile.go
func (t *Tile) NextPos() (int, int) {
	return t.next.x, t.next.y
}
func (t *Tile) NextPos() (int, int) {
	return t.next.x, t.next.y
}
// NextPos returns the tile's next position.
// NextPos is used only at testing so far.