Mercurial Eye

The Mercurial Eye, powered by a Klein Star, turns raw EMC into your choice of block and places 'nicely stacked walls' of the target block or smooth walls. If you want, the Mercurial Eye can transmute the target block into a block of your choice using the existing block's EMC to defray the cost of replacing.

Uses
The Mercurial Eye has the power to build walls straight from the energy source of a Klein Star. To change the area covered by the Eye, press the (Charge Key [V]). To open its GUI, press the (Extra Key [C]). To change mode press (Toggle Key [G]).

To decharge the eye and make the area smaller you must sneak/crouch(shift key) and press the charge key (v).

Eyes are attached to their users - if you lose or destroy one with a Star or targeted block still within, the internal inventory will persist until you get a second one.

Upon opening, you will see a target slot, used to select the block of choice, and a Klein Star slot, which you are required to give a source of power. It's possible to place non-block place-able items in the Target slot, such as Ladders or torches, but the item will not be placed correctly, and will drop once the block is updated. The Mercurial Eye has 4 modes:
 * Creation Mode - This mode acts as if you were holding the target block; useful for precision work. Be careful - the Eye does not care for your location when placing the block down.
 * Extension Mode - The wall you are building extends from existing structures. This is extremely useful for things such as aiming down and creating bridges. Your position relative to the aimed face determines how the extension is oriented. Requires charge, which lays down blocks in a square around the aimed block.
 * Pillar-Extension Mode - This mode creates a huge pillar which extends in the opposite direction of the aimed face, i.e. away from you. Requires charge. Do not fire upwards. At full charge it creates a 3x3x50 pillar in the direction you are aiming.
 * Transmutation Mode - Whatever your target block is, it will transmute the blocks you target to, similar to extension mode. If the EMC of the changed block was greater than your target, you absorb the EMC. If it was less, you spend EMC. If it is the same, the power costs nothing! This function can be very helpful for building in a material that is particularly difficult to remove, such as obsidian. Rather than building with obsidian, simply build in dirt or another easily cleaned up block, then convert it into obsidian when the structure is done.

Problems

 * When placing an item (such as a door) in the "block" section of the Mercurial Eye and attempt to place it, the world will crash. However, you are still able to load the world. (SSP Tested)