Mirror-QWERTY is a keyboard input modifier that allows touch-typing with one hand. It does so by mirroring the keyboard when the spacebar is being held down, granting access to the entire range of typeable characters from either single side. It runs in the background, making it practical for use with any application.
While this app has an interface and functionality nearly identical to One-Hand Keyboard, the developer's commercial offering, its operating principle is different. While One-Hand Keyboard relies on word prediction through a dynamic dictionary, Mirror-QWERTY simply alters the input based on whether the spacebar toggle is activated - a method that some may actually prefer for its greater method of control, not to mention the pricing discrepancy!
The mechanism of using the spacebar for keyboard flipping is quite ingenious really. Since touch typists use the thumbs of each hand exclusively for the spacebar, holding the toggle does not interfere with the typing of other letters, and either the left hand or right hand can use this technique.
Sam's Protip: While the app is designed for those with injuries to one hand, there are any number of situations where typing quickly with just one hand could come in handy!