In a busy city there lived a crow that adored walnuts, although their shells were far too hard for its beak. For weeks it hopped around the parking lots, hungry and frustrated. Then, one afternoon, it noticed a car roll over a walnut that had fallen on the road. There was a sharp crack, the shell split open, and the crow understood.
From that day on it had a plan. It carried a walnut to the zebra crossing, dropped it in the path of the traffic and flew up to the traffic light to wait. The cars rolled over the nut and cracked it. Then the light turned red, the traffic stopped and the pedestrians began to cross, and that was the moment when the crow hopped down, calm and unhurried, to collect its lunch.
An old man called Mr. Sato, who fed sparrows on a bench beside the crossing, watched this performance every day. At first he could hardly believe it. After a few weeks he began to bring walnuts of his own and place them on the road, as if he were part of the plan. Years later the crow returned to the crossing with its young and taught them exactly the same trick.