When providing a picture or an 3D object as a captcha - in which LANGUAGE do you expect the users to answer?
Do you really believe that the whole world has to be fluent English (or whatever your native language might be) speakers to solve them? What about the whole rest of the world?
What about people who know what they see, but cant type in its name correctly? Is it a bunnie? A bonny? A buny? Or a bunny? Or is it a hare? A hair? Captcha solving is not meant to be an orthography test after all...
Think again and youll see - epic fail!
The earth is like a tiny grain of sand, only much, much heavier.