A crow, half-dead with thirst, came upon a pitcher that had once been full of water. When it put its beak into the pitcher, it found only a little water remained at the bottom, far out of reach.
The crow tried again and again, but finally had to give up in despair. Then, an idea came to it. The crow picked up a pebble and dropped it into the pitcher. It then picked up another pebble and dropped it in, and then another, and another.
At last, the water began to rise. After dropping in a few more pebbles, the water level was high enough for the crow to drink. It quenched its thirst and saved its life.
Little by little does the trick.