Don't be afraid to stumble. Any inventor will tell you that you don't follow a plan far before you strike a snag. If, out of 100 ideas you get one that works, it's enough.
Charles KetteringGreat steps in human progress are made by things that don't work the way philosophy thought they should. If things always worked the way they should, you could write the history of the world from now on. But they don't, and it is those deviations from the normal that make human progress.
Charles KetteringI often say that research is a way of finding out what you are going to do when you can't keep on doing what you are doing now.
Charles Kettering