This mod adds two new tools for quick block duplication. They can help to assemble bridges in a snap for either escape or simply creating the foundation for further construction. The basic Transtructor will allow you to duplicate up to 16 blocks from the first one and the advanced Transtructor can go up to 64. All you need is to have the same blocks in your inventory.
This can work extremely well for those treacherous lava pools in the Nether.