5 tiles is a brilliant example of designing from 1st principles.
It is an android keyboard, designed specifically for touch-screens to keep the screen free for content. I'm slowly beginning to pick it up.
I guess it's similar to the sort of one -handed keyboards used by divers.
It is a very different proposition from Google's keyboard or Swiftkey which try and learn about you and predict what you are typing using your data.
Instead it is asking you to invest time in learning a new system that allows a new freedom - more screen size (or the ability to type underwater for the diving analogy).
I've also been using duckduckgo as default search engine for a couple of weeks as primary search engine on mobile and laptop.
It stands up pretty well, but the best feature is !bang which builds commands to search other websites, like StackOverflow or Google Maps directly, directly into the core search. URLs as interface.
In use, it feels similar to the sort of commands you find in vim and other text editors.
I have a hunch that more alternative/complex input methods are going to start to become naturalised in more mainstream UI.