Bridge builder

In the Madd Games Mod for Minecraft, a bridge builder is a machine that can be used to construct bridges. It can be used, for example, in the Nether, to make bridges across lava, as it does not require you to be able to get to the other end to construct.

Crafting
A bridge builder can be crafted from:
 * 7 x iron ingot
 * 1 x redstone
 * 1 x cobblestone

Usage
You place the bridge builder at any location, where you want to begin construction. Next to it, you put a marker block, to mark the direction in which the machine should build. If the marker disappears, it means the builder has been initialized. Now put some kind of chest on top of the machine, and fill it with material. You will see how it quickly removes the material from the chest and constructs a bridge. If it runs out of material, just put some more in the chest, and it will continue building. Once it reaches a wall, the machine will reset itself.