If there's anything I can tell from my limited ergonomics education, it's that it's probably more ergonomic if the design looks more melty/wavy/putty-like. I mean, this design already looks more comfortable and I haven't even tried it yet.

I like the horizontal but micro-filleted cutouts for the keys more than the slot cutout alternative I thought of:

The filleted cutouts make the design look more compressed and remind me of refinement, like a piano.

The motorised strat is really going to make this solution BetterTM than my earlier ones. The motor can create virtual endstops so that I always know when I hit the limits. It can also have weak dedents for accurate finger positioning. Actually, it might mean that users could manage 5 or dare I say 6 discrete zones on the finger keys and/or 3+ on the thumb button. I'm imagining that the extra thumb zones would be used for accents in other languages. I might have the "MouseChord" use dedents to get finer mouse positioning than the standard 4 zones.

(5 zones results in a Base16 (hex) number system, which might be pretty cool. Imagine LED backlighting where the colour is determined by the chord. Idunno if anyone would need the equivalent of a 4095 button keyboard though -- a Chinese/Japanese speaker maybe?)

Obviously, it's going to be an eye-grabber (if such a large, white wearable wasn't grabbing enough) if some kind of idle movement animation is enabled. If I learned anything from Apple's event yesterday, it's that good animations sell "the future is now, thanks to science".

I'm also glad I slept on a solution instead of thinking that I'd never be able to get a motorised key without making Turntable (and #Tetent Tiny [gd0040]) drastically thicker. Having the belt offset to the side instead of the centre actually helps because now the 4th digit can come in from an angle without any obstructions.

I also hope that the belt and motor assist means that I could actually walk while typing. I think the current set of features allows it to be possible.

I'm currently not a fan of the look of the thumb when I put it in my "standing visualisation" file: