Eaten on
重阳节 (9th day of the 9th lunar month). Because
糕 (gāo, 'cake') sounds exactly like
高 ('high'), eating it is a homophone substitute for the festival's traditional
登高 'climbing high' ritual — a way to claim the blessing of ascension without actually having a hill nearby. Typical forms: multi-layered rice-flour cake studded with jujubes and nuts, topped with small colored pennants.