Carry save adder

[EDevil]

After Chibill's post (read it here!) i thought of making a fancy adder myself, which i've never tried out before as well. I already made it in Logism today, so making it in Minecraft shouldn't take that long. Basically, why this adder is so special is that it does not have 2 inputs (A &B) but four of them (A, B, C, and D).