Nether Reactor

The Nether Reactor is a player built structure which, when activated, spawns large quantities of normally rare or unobtainable items.

Structure
The reactor is constructed by placing a gold blocks, cobblestone, and a nether reactor core in the 3x3x3 arrangement shown above. Air blocks are required on the middle and top layers. If the structure is incorrect, attempting to activate the reactor will result in the client message "Not the correct pattern!".

Behavior
Tapping the core will activate the reactor, sending the client message "Active!". Immediately after activation, the reactor will spawn a massive 35×17×17 structure of netherrack with multiple floors, unofficially called a "Nether Spire". Any block in the way of the spire will be replaced. The blocks that make up the reactor, excluding the core, will turn into glowing obsidian.

In addition, it will start spawning various items and blocks. These can be melon seeds, glowstone dust, both types of mushroom, cacti, sugar canes, pumpkin seeds, and nether quartz as well as zombie pigmen. Due to this great variety of items, it is advisable to empty out one's inventory beforehand so that no items are missed, other than any weapons used to fight the zombie pigmen (unless playing in peaceful difficulty). After it burns out, the spire with multiple floors will have many holes in its walls. The bottom floor is hollow (all blocks inside other than the reactor are replaced with air), and the upper floors retain the blocks that were already there (air for an above-ground spire, dirt/stone/etc. for an underground spire). The core is still there, and is reusable. The used core is found in a 3×3×3 obsidian box where the reactor was constructed. When the reactor is active, the core's texture will change to red, and when the cycle is complete, it will change to a blackened texture.

The zombie pigmen who spawn are hostile to the player, and will burn (though not get hurt) in sunlight, unlike the ones in the PC or console editions. Their texture and animations are also slightly different. When a zombie pigman is killed it drops feather(s) and gold ingot(s), allowing you to multiply your gold source if you recover the blocks.

The reactor is not currently functional in Creative mode.

Conditions

 * All players must be within the spire's area.
 * If the reactor is to be activated above water, it must be built at least three blocks above water.
 * The reactor must be built low enough for the spire to fully generate, as blocks cannot be created above cloud level.
 * The player must not be standing on a block below the last layer of the reactor.

Trivia

 * In total, the reactor requires 6 iron ingots, 3 diamonds (the core), 36 gold ingots (4 gold blocks) and 14 cobblestone (rest of the structure) to create.
 * The structure created by the reactor, the Nether Spire, is 17×17 blocks at its widest (bottom) and is 35 blocks high (2 blocks low and 33 blocks high).
 * The spire has over 25 stacks of netherrack.
 * The air blocks in the pattern are not optional. This means the player cannot build the reactor underwater unless you waterproof the air blocks in the pattern.
 * The player can quickly mine some or all of the materials out of the reactor after activation and it will still function. This way the player can recycle the expensive gold blocks. Another alternative method is to simply have someone else help mine the blocks right after activation. If they're fast enough, they'll have time to mine all four gold blocks with a diamond pickaxe before they turn to obsidian.
 * If the player mines the active core, the glowing obsidian will not turn into normal obsidian.
 * There is an elevation limit for the reactor, above which it cannot be activated.
 * If the player builds a reactor around the burnt out core, the spire will generate, but no items or zombie pigmen will spawn, the cobblestone and gold blocks do not turn into glowing obsidian, and the core remains in its activated state unless mined, making a netherack farm.
 * The spire cannot replace blocks past the world border in old worlds.
 * If activated here, the player will be able to see the time set to night.