Myles Lee (aka mylestunglee) published this PCB with two snap-off blocks. The articulation80 supports up to 4x9 keys (plus thumb cluster).
I've always wanted a keyboard with arrow keys, whether that's for my office work or gaming. I first tried the Quefrency, then moved on to using the Breeze keyboard. I wanted something from both, enough keys but not too many – Myles.
Inspired by keyboards like the Breeze, Kyria, Hillside 52 and Corne, the articulation80 PCB has snappable numpad and number rows except the corners, allowing easy access to escape or backspace.
By the way, the name is a reference to articulated buses, since this keyboard has many connected blocks with splay too.
I was also keen on experimenting on reducing keyboard latency, so the PCB supports serial and I2C connections, not something I see often when I was investigating many open source designs – Myles.
In addition, the author wanted a clean design, and used FreeCad to parametrically design the PCB for his hands.
Specs
44-80 keys
low profile, Choc spacing, hotswap
detachable numpad
detachable inner number row (fixed outer number row)
Pro Micro-compatible controller footprint
serial or I2C connection between halves
Nothing on the silk screen, if you are building this, you may want to add some hints to make soldering easier.