ArrayList<Block> lakeBlocks = new ArrayList<>();
for (int i = -1; i < 4; i++) {
Vector center = new BlockVector(rx, ry - i, rz);
for (int x = -radius; x <= radius; x++) {
for (int z = -radius; z <= radius; z++) {
Vector position = center.clone().add(new Vector(x, 0, z));
if (center.distance(position) <= radius + 0.5 - i) {
lakeBlocks.add(world.getBlockAt(position.toLocation(world)));
}
}
}