iPhone – Make a Mistake… Just shake it
New to iPhone, made a mistake typing, deleting, cutting, or pasting and wondering how to undo it? While you might have already figured this out through unbridled frustration. If you’ve been editing some text and you either typed the wrong thing, deleted more than you intended to, or cut, copy, or pasted yourself into error-land, here’s what you do:
Hold you iPhone firmly in one hand
Shake it (Really)
Tap the Undo button to confim
Apple has built “shake to undo” into the iPhone since iOS 3 and it works really well.