Have your ever watched crabs at the seaside? If you have, you'll notice that they never walk straight, but always sideways. Once, though, there was a mother crab who ran about without ever thinking. When she was doing. When she saw her son rushing sideways from pool to pool she thought something must be wrong with him. "Stop, stop," she cried in alarm. "Try to walk properly, like a grown-up crab. Put one leg in front of the other."
Her son was wiser than she was "All right , mother," he said. I'll watch exactly how you do it and do the same." And of course he went on walking sideways!