public class ExampleHolograms implements Listener {

    private final Plugin plugin;
    private final HologramPool hologramPool;
    /**
     * @param plugin The plugin which uses the lib
     */
    public ExampleHolograms(@NotNull Plugin plugin) {
        this.plugin = plugin;
        this.hologramPool = new HologramPool(plugin, 70);
    }

    /**
     * Appends a new Hologram to the pool.
     *
     * @param location  The location the Hologram will be spawned at
     */
    public void appendHOLO(@NotNull Location location) {
        // building the NPC
        Hologram hologram = Hologram.builder()
                .location(location)
                .addLine("Hello World!")
                .addLine("Using Hologram-Lib")
                .addLine("Hello %%player%%")
                .addLine(new ItemStack(Material.IRON_BLOCK))
                .addPlaceholder("%%player%%", Player::getName)
                .build(hologramPool);

        hologram.getLines().get(3).setAnimation(Animation.CIRCLE);
        // simple changing animating block and text
        timingBlock(hologram);
    }

    private final static Material[] materials = new Material[] { Material.IRON_BLOCK, Material.GOLD_BLOCK, Material.DIAMOND_BLOCK, Material.EMERALD_BLOCK};

    /**
     * Update the block and the first line of text of the hologram
     * @param hologram The hologram to update
     */
    private void timingBlock(Hologram hologram) {
        new BukkitRunnable() {
            int j=1;
            final TextLine firstLine = (TextLine) hologram.getLines().get(0);
            final ItemLine itemLine = (ItemLine) hologram.getLines().get(3);
            @Override
            public void run() {
                if(j==materials.length) j=0;
                firstLine.set(String.valueOf(j));
                itemLine.set(new ItemStack(materials[j++]));
            }
        }
        .runTaskTimer(plugin, 30L, 30L);
    }

    /**
     * Doing something when a Hologram is shown for a certain player.
     * @param event The event instance
     */
    @EventHandler
    public void onHologramShow(PlayerHologramShowEvent event) {
        Hologram holo = event.getHologram();
        Player player = event.getPlayer();
    }

    /**
     * Doing something when a Hologram is hidden for a certain player.
     * @param event The event instance
     */
    @EventHandler
    public void onHologramHide(PlayerHologramHideEvent event) {
        Hologram holo = event.getHologram();
        Player player = event.getPlayer();
    }
}