Fornjot is a CAD program that is written in Rust. In addition, CAD models in Fornjot are defined as code, and Rust is also the language used for doing that. You can learn more about Fornjot at the website: https://www.fornjot.app/
I'm publishing a weekly dev log at the Fornjot website, which I will also post here. Feel free to subscribe to this thread, if you want to follow along!
Here's the link to this week's dev log: Fornjot - Weekly Dev Log - 2022-W06
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W07
I made some progress preparing for the upcoming work on constructive solid geometry (CSG) operations, then got distracted by some annoyances with the math types Fornjot uses, which lead to a massive cleanup effort.
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W08
It's been another week of finding problems, and then finding solutions to those problems that make the CAD kernel more flexible and robust. If you have any questions (about this dev log or Fornjot in general), feel free to post them here!
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W09
Highlights include me getting side-tracked to work on more cleanups to improve the CAD kernel's robustness, yet again 
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W10
This time, the highlight is that I finished a big cleanup that should hopefully pay dividends going forwards. If you have any questions, please don't hesitate to post them here!
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W11
Lots of progress this week! Wrapped up some cleanup work that has been going on for a while, and started addressing some smaller issues that have been open for too long.
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W12
It was a bit of a slower week, but stuff got still done. Unfortunately, a lot of it sits unfinished on my office PC which is currently out for repair, but that's life
I've been working on #141, which went pretty well until I started to extract the triangle mesh data structure into a separate crate. I realized that this code could use a good cleanup, which required changes to the triangulation code (#105), which required more clean-ups... the usual virtuous cycle of getting distracted by more and more productive tasks.
Ah, the good 'ol "oh this code is a bit messy so let's just rewrite it" rabbit hole 
Well, it's always a balance. Touching up that kind of code as you move past it makes sure things stay reasonably clean. Overdoing it means you never get anything done, because you're always bogged down in unrelated cleanup work.
In this case, the whole point of #141 is to make it possible for an ecosystem to develop around Fornjot, so I think it makes sense to make sure each library I extract has a minimum level of quality.
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W13
No real highlights this week, as I had to deal with the fallout from my broken computer. Good news is, I got all the data off of it, and have been getting back into my groove.
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W14
Highlights this week include wrapping up the work on triangulation testing infrastructure, and fixing a bunch of the worst triangulation bugs.
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W15 (Pre-Vacation Edition)
This one's a few days earlier than usual, as I'll be on vacation for the next two weeks. I managed to squeeze some good work into the last few days though, finishing up the effort of splitting the Fornjot app into self-contained libraries, as well as fixing a bunch of bugs.
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W16/W17 (Post-Vacation Edition)
I'm back from vacation now, so those will actually come out weekly again from now on
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W18
Highlights this week include a new release being out, and the return to work on constructive solid geometry.
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W19
Highlights this week include progress on implementing the union operation, and finding new and interesting detours.
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W20
On a high level, work continues on implementing the union operation, but there are lots of things to improve and clean up, to be able to do that without creating a big mess.
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W21
Highlights this week include the implementation of geometric validation, which has already contributed to finding some bugs that held up the ongoing cleanup work.
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W22
Highlights this week include me being a bit stuck, and awesome contributions kind of making up for it.
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W23
This week was a bit slow, but had a bit of a breakthrough at the end!
The new Weekly Dev Log is out: Fornjot - Weekly Dev Log - 2022-W24
This ones features a lot of deep thinking!