There are quite a few apps that can do this. Nobo comes to mind. They just don’t feel that useful. For complex work, typing on a keyboard and using a cursor at

There are quite a few apps that can do this. Nobo comes to mind. They just don’t feel that useful. For complex work, typing on a keyboard and using a cursor at the same time is much more productive. (this comment typed one-handed using the iPhone’s swipe keyboard)