The "Picture of the Turning Sphere", a famous reversible poem woven into a piece of brocade by [[苏蕙|蘇蕙|su1 hui4]] of the Jin dynasty to express her longing for her exiled husband; its 841 characters can be read in thousands of different ways to form unique poems.

ancient astronomical instrument for measuring the movements of celestial bodies; refers to both a specific historical sighting tube and the broader concept of the Big Dipper constellation