Parikrama by Ganesha

Ganesha and his brother Kartikeya were once in a competition to see who could circumambulate the Earth the quickest. While Kartikeya took off on the long journey in a hurry, Ganesha devotedly circled his parents Shiva and Parvati instead. Why traverse the physical expanse of the Earth when the universe resides in one's parents?
This story forms the main body of Ganesha, with "Matru Devo Bhava, Pitru Devo Bhava" residing within Ganesha's path and "Ekdantay Vidmahe Vakrtunday Dheemahi" forming the trunk.