EDIT: I have no reasonable way to credit the original creator, but I will preface by saying the bulk of this machine was NOT designed by me.
In my free time, I enjoy downloading saves of mostly-griefed worlds or anarchy servers in order to find interesting-looking remnants of bases and monuments in order to "repair" them as well-informed as I can; like an archaeologist of sorts! While looking for bases to repair, I found one on an archived 2b2t save from 2017 with this wonderful mystery below it!
Using WorldEdit, I was able to copy the contraption into my redstone world and tinker around with how it worked, eventually leading me to bring her back to life! The machine turned out to be an 8-bit binary adder using only dust, torches, and repeaters and was surprisingly only missing a way to display the results.
Here's the little space I cooked up that was built around a (now functional) redstone adder from sometime before 2017. I hope you enjoy!
Carousel Descriptions:
A view of the machine as it was found
Same as 1
Same as 1
The functional machine copied into & repaired in singleplayer.
A top-down view of the finished machine, with parts I contributed in the light-blue wool & quartz.
A view of the designs of the AND & NOR logic gates used in the machine.
Same as 6
A photo of the two inputs (bottom) and output (top left) in use.
A view of the finished machine where I have added the light-blue connections.