lately I have been working on a digital logic system for Blockland, giving possibilities for both simple binary machines and numerical calculations built with Wire bricks and Logic Bricks.
here's a video of a binary adder:
http://youtu.be/mPd--MmfE0UAll Ray-casting is done while building, or deleting bricks. when finished, 1 global tick updates the Logic Bricks (only if they need to be updated). current Logic Bricks are: Wires, NOT, AND, NAND, OR, NOR, XOR, Adder, Multiplier, GreaterThan, Equal-To and a positive clock edge D-FlipFlop.
BETA RELEASE 3:(please report bugs to this thread)
http://dl.dropbox.com/u/4223056/Brick_Logic.zipWires not only work with on or off values but also can work with floating point numbers.