Forums - Open Redstone Engineers

My English knowledge isn't too good.
Special thanks to DJSapsan he's my favorite redstone engineer.

Minecraft name: True_han (r.n. pitblue)
What do you like the most about redstone?: Logic, ALUs
What's a thing you have made which demonstrates redstone knowledge?:
Postal office (few logic);
PC without ALU;
My first compact carry adder (without Minecraft guides!);
many more...
What does it do?:
Postal office sends minecarts to houses using buttons;
PC without ALU can print text on screen.
I guess you know what adder does xD
Image and/or video, from imgur.com or youtube.com:
Postal office (without decoration): https://youtu.be/lvfCvv02DQg (that vid is russian I can translate for you); 
PC without ALU: https://imgur.com/7T1eibu https://imgur.com/d4LHByJ
You can find adder on my school plot.
What do you plan on making for your build trial?: Build my first PC with ALU
Do you agree with the rules?: Yea

Can you talk more on what you mean when you say "PC"? We focus on computational redstone so the ALU is the most intriguing part.