Comment by jsheard

See also the Soufflé, a further derivative which makes the vertical stagger more aggressive as has become the fashion for most newer ergo boards:

https://github.com/climent/SouffleKeyboard

If you go any further down the ergo rabbit hole you'll probably end up with fewer keys than that though, typically 34-36 in total, e.g:

https://github.com/davidphilipbarr/Sweep

https://github.com/pashutk/chocofi