This command allows you to use multiple new commands in Minecaft (~30) ! You can write them in a special book, and the are executed. You can become a god, or summon lightning bolts, mute the mobs, and a lot of other things ! Tutorial in french.
This command (1.9 & 1.10) is a very special one, which doesn't do anything particular : in fact, it's an useless-machine ! You push the lever, and a mechanical arm retracts it whith a pretty smooth animation. Tutorial in french. In the video, the animation is at 2:32.