I'm posting here at the request of Dylan.
I present to you...
The MOS-Tron Envelope Filter
based on the Chewborg Envelope Filter provided here.
Here are a couple pictures of the project:


More pictures and details for this project can be found on my GitHub repo. This project includes files for the top board, bottom board, and build documents (which includes a drill template and a link to a pre-designed template for Tayda's Drill Tool).
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, the same as the original Chewborg Envelope Filter.
If you've been on the fence about trying this project, I'd recommend trying it. Happy building!