Minecraft 4-bit adder

[Weezy]

I created it anyway. I really studied how do the logic gates, binaries and adders work and spent like week doing this. Well the planning of the decoder what converts binary answer to the hexadecimal display took most of the time, placing the redstone surprisingly didn't. The plans I made in cool tool called redstone simulator. Oh and yes, I used INVedit, it would be retarded to mine this all. But In my legit save there's 2-bit version with simple binary display =P