The circle of life

There was once this wooden cirlce. He was pretty content. Just one teeny weeny thing nagging him though. He had a small part of his circle missing, a little sector that was not there.
He would roll around all day, talk to the grass, the warm earth and the little purple flowers in its bosom, the blue skies and the birds from far away. It made him happy, but for that small nag. He would try to complete himself, try and find little pieces that fit his hollowness. They never were right, and he continued his journey. Listening to the moon laugh.
To his luck one afternoon, he found this piece of wood. It looked just right. He tried it on. Voila! It fit perfectly too! He beamed with joy and rolled on the same warm earth so fast, he was finally complete!
He went on, deliriously, amazed at how he thought this piece completed him. Ah, to be free finally.
Oddly, he sometimes still felt heavy. He never listened to the birds anymore. Or a babbling brook. The rustle of orange leaves in autumn. This time however, he knew what to do. He gave the piece up. And he realised he had come a full circle.