Napoleon Hill, Think and Grow Rich, 1960.
Automobile genus Henry Ford once came up with a revolutionary plan for a new kind of engine which we know today as the V-8. Ford was eager to get his great new idea into production. He had some men draw up the plans, and presented them to the engineers. As the engineers studied the drawings, one by one they came to the same conclusion. Their visionary boss just didn't know much about the fundamental principles of engineering. He'd have to be told gently&md;his dream was impossible. Ford said, "Produce it anyway." They replied, "But it's impossible." "Go ahead," Ford commanded, "and stay on the job until you succeed, no matter how much time is required."
For six months they struggled with drawing after drawing, design after design. Nothing. Another six months. Nothing. At the end of the year Ford checked with his engineers and they once again told him that what he wanted was impossible. Ford told them to keep going. They did. And they discovered how to build a V-8 engine.