kagami mochi, n.All

Kagami mochi is shared round to represent the heart

Kagami mochi is stacked around the house in order to look like a round copper'kagami'(_, mirror) that was used in ancient Japan

Kagami mochi is topped with a type of orange called daidai, which is a homonym for 'daidai' meaning 'many generations', with the implication that one would achieve this.