All current keyboards are sequential. Even when you press more than one key at a time, you must press one of those keys first--shift-e is not the same as e-shift. It strikes me that this is inefficient. We are capable of pressing 10 keys at a time. What if a keyboard were made so that many letters could be pressed at the same time (or within a very short interval) where the order doesn't matter, and the computer could figure out what you intended? For example: To type the word "chair," I must currently press the c, then the h, then the a, then the i, then the r. I can do this in a fraction of a second, but it's still one at a time. Instead, on a Parallel Keyboard, I might press all the letters at once (the keyboard would be set up to make it easier for me to do this) and the computer would instantly recognize that the only possible arrangement for those 5 letters is "chair." If I had pressed "ploo" (the keyboard would have duplicates of common letters like o and e) the computer might give me the options "loop" (option 1), "pool" (option 2), or "pool" (option 3). I'd press 3, using 2 keystrokes instead of 4. It seems like you might easily get 200+ WPM on a keyboard like that, once you learned how to use it.