There was a man who sat each day looking out through a narrow vertical opening where a single board had been… — Frank Herbert

There was a man who sat each day looking out through a narrow vertical opening where a single board had been removed from a wooden fence. Each day a wild ass of the desert passed outside the fence and across the narrow opening — first the nose, then the head, the forelegs, the long brown back, the hindlegs, and lastly the tail. One day the man leaped to his feet with a light of discovery in his eyes and he shouted for all who could hear him: "It is obvious! The nose causes the tail!"

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