Parametric equations for circles

Circles.groovy

import net.year4000.ducktape.bukkit.DuckTape
import net.year4000.ducktape.bukkit.module.BukkitModule
import net.year4000.ducktape.bukkit.module.ModuleListeners
import net.year4000.ducktape.module.ModuleInfo
import org.bukkit.Bukkit
import org.bukkit.event.player.PlayerInteractEvent
import org.bukkit.event.EventHandler
import org.bukkit.event.Listener
import org.bukkit.Material

@ModuleInfo(
    name = "Circles",
    version = "0.0.1",
    description = "Parametric equations for circles.",
    authors = ["ewized"]
)
@ModuleListeners([Circles.class])
public class Circles extends BukkitModule implements Listener {

    /** Print out the origin location */
    @EventHandler
    public void onPunch(PlayerInteractEvent event) {
        int x = event.getPlayer().getLocation().getBlockX()
        int y = event.getPlayer().getLocation().getBlockY()
        int z = event.getPlayer().getLocation().getBlockZ()

        event.getPlayer().sendMessage(String.format("%d, %d, %d", x, y, z))

        circle(event, x, z, y, true);
    }

    /** Draw a circle and more circles again */
    public void circle(PlayerInteractEvent event, int x, int z, int y, boolean first) {
        Bukkit.getScheduler().runTaskAsynchronously(DuckTape.getInst(), new Runnable() {
            public void run() {
                double radius = 16;

                for (int i = 0 ; i < 90 ; i++) {
                    int xx = x + (radius * Math.cos(i));
                    int zz = z + (radius * Math.sin(i));

                    Bukkit.getScheduler().runTask(DuckTape.getInst(), new Runnable() {
                        public void run() {
                            Material material = event.getPlayer().getItemInHand().getType()
                            material = material == null ? Material.AIR : material
                            material = !first ? material : Material.DIAMOND_BLOCK
                            event.getPlayer().getLocation().getWorld().getBlockAt(xx, y, zz).setType(material)
                        }
                    })

                    // Draw a circle one layer deep
                    if (i % 10 == 0 && first) {
                        circle(event, xx, zz, y, false);
                    }
                }
            }
        })
    }
}