Literature Reference: On the beam, a pair of swallows, graceful and elegant, build their nest between two rafters, raising four chicks. The chicks grow day and night, chirping incessantly for food. Catching green insects is no easy task, and the young ones are never satisfied. Though their beaks and claws grow weary, their hearts and strength remain tireless. In moments, they fly back and forth, fearing the nest may go hungry. After thirty days of toil, the mother grows thin while the chicks grow plump. She murmurs, teaching them words, and meticulously grooms their feathers. Once their wings are fully grown, she leads them to the branches of the courtyard tree. They flap their wings and fly away without looking back, scattering with the wind. The parents cry in the air, their calls unanswered, and return to the empty nest, chirping in sorrow all night. 'Oh, little swallows, do not grieve; reflect upon yourselves. Think of the days when you were fledglings, flying high and leaving your mother behind. What your parents felt then, you should now understand.' Source from 'Yan Shi Shi Liu Sou' by Bai Juyi.