www.logiccircuit.org

It's a 4 by 4 array of LEDs!
The LEDs are controlled by the LED chip, which takes an Row input and Y coordinate and activates the corresponding LEDs.
The Y coordinate and Row input are pre-programmed with the ROM chips. The ROM for rows is the top one, the ROM for Y is the bottom one.
The part with ...

It should give incorrect results if the sum is more than 15 because it overflows at that point (the output is a 4-bit number, and the highest decimal number that can be represented in 4 bits is 15)
If that isn't what is happening, the I've messed up somewhere lol

I'm back after so long :P
I've made a device that adds 4-bit numbers, but also displays them and the sum with the 7-segment display.
I know that an LCD controller chip already exists, but I think the one I've made is more efficient and organized. Rather than many AND gates and arrays of wires, I've ...

Done! And reduced file size by quite a bit by basing the byte adder off of smaller adders.

It adds bytes! Pretty simple, but it's my first actual accomplishment with LogicCircut. Sorry about all the wires and such :P. The bytes run vertically, with the 2^7 place on the top. So, 10001011 looks like:
1
0
0
0
1
0
1
1
You add the first two bytes (first two columns) and the result is the third ...