Hey there!

I made an adder/subtractor (unnecessarily 8bit)
combined with a 3.5 digit 7-segment display (4 bit) for input and
output. (Wich means decimal input and decimal output)
It can also calculate to negative values.

This
ALU (arithmetic logic unit) is bigger than the area that get's loaded
into the RAM. It requires a second player just standing at the
SheepTower™ in order to work.

I also made a mine cart tour around this circuit.

I hope you enjoy it :-)

Here is the video:
http://www.youtube.com/watch?v=UF2Vk3RVUls