As a weird aside here I've actually done a major UX research project on how people with one arm or one hand type.
It got me nominated for a design for experience award.
You can read the article here:
http://www.uxbooth.com/articles/...
Love this keyboard! Since the new iPhones are a bit too big for one handed typing, this app wants to help you out so you can "reach all the letters with just your thumb, especially on the biggest iPhones". Changing the color of the keys is a nice touch. For me this is the first 3rd party keyboard that actually works. Some hidden features: "Hold down the space bar to change between full mode and one-handed mode. Light mode is enabled in applications such as messages, dark mode is enabled in places such as spotlight, both automatically."
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