This half keyboard for PDAs is intriguing because it capitalizes on a cognitive trait. Your brain corresponds your left hand fingers to your right hand fingers symmetrically. Your brain can easily map the Qwerty layout “L” from the right ring finger to the left ring finger, so when you put this keyboard into shift mode, you can do a sort of mirror adjustment in your reactions. It does take some training, but compared to learning a completely new layout (or even hand writing), it wins by a mile. (via Memepool)