posting this here as anybody who is slightly interested in different keyboards would enjoy this read and the 99% episode about it
Left to Write is a three-article set about adaptive writing technologies for one-handed users. This first piece explores accessible keyboards; the next details the process of developing a new keymap for comfortably touch-typing with one hand on a conventional two-handed board; the third explains how to convert your own QWERTY into a single-handed KURTY.
No mention of the twiddler
Or the frogpad
That mirrored mode is interesting and made sense to me even before I read the explanation. I’d assumed it only makes sense for using the left hand and that using just the right would need a different version of the keyboard, but there doesn’t seem to be a flipped version.