See this little 1 block deep pit thingy? Result of it: Lots of little holes like these can lead to caves, ores, ravines, lava, anything found underground. (usually ravines or deep caves, and very rarely dungeons.) See this? This is nearby the other example I displayed. It's 1 block higher instead of lower. Result of this one: This one wasn't very good. Kinda like gambling for loot. Sometimes you dig straight to iron, sometimes diamonds (kinda rare for me) it depends on luck (if you believe in it) or the science and geography of Minecraft. Hope you enjoyed this. Edit: This also works in mini-games that allow building/destroying such as Battledome, Walls, Hunger Games (that allow up to 100 players and has destroying/building and feasts and mini-feasts), and games like those. If you have questions THAT IS FRICKEN RELATED TO THIS TOPIC, please don't hesitate to reply below, I'd be more than glad to answer 'em.