BlockBeacon.java

    public static void updateColorAsync(final World worldIn, final BlockPos glassPos)
    {
        HttpUtil.DOWNLOADER_EXECUTOR.submit(new Runnable()
        {
            public void run()
            {
                Chunk chunk = worldIn.getChunkFromBlockCoords(glassPos);

                for (int i = glassPos.getY() - 1; i >= 0; --i)
                {
                    final BlockPos blockpos = new BlockPos(glassPos.getX(), i, glassPos.getZ());

                    if (!chunk.canSeeSky(blockpos))
                    {
                        break;
                    }

                    IBlockState iblockstate = worldIn.getBlockState(blockpos);

                    if (iblockstate.getBlock() == Blocks.BEACON)
                    {
                        ((WorldServer)worldIn).addScheduledTask(new Runnable()
                        {
                            public void run()
                            {
                                TileEntity tileentity = worldIn.getTileEntity(blockpos);

                                if (tileentity instanceof TileEntityBeacon)
                                {
                                    ((TileEntityBeacon)tileentity).updateBeacon();
                                    worldIn.addBlockEvent(blockpos, Blocks.BEACON, 1, 0);
                                }
                            }
                        });
                    }
                }
            }
        });
    }