The waterwheel makes sure that the field will not dry out. The slow and constant supply of water makes the plants grow harmoniously, without stagnations, abundant.
The wild goose can only reach its far-away destination, and come back every year, by beating its wings second after second, never losing its strength or direction.
Every relation needs a constant supply of water, of feelings, regular love, day after day.
Starting something is usually not the most difficult part; it is harder to keep it going. Every day caring for it, feeding, repairing: every creation has to be kept alive day after day, year after year.