What are some symbols used in Yom Kippur ceremony?

The Yom Kippur ceremony? That's an odd turn of phrase. There are no symbols used in the Yom Kippur service that are not used in just about every Jewish service. Torah Readings, prayer shawls, all of that is routine. There are two symbolic elements that are unusual. One is that it is traditional to wear prayer shawls after sunset on the eve of Yom Kippur. This is not usually done. The other is that the service at the very end of Yom Kippur ends with a prolonged blast on a shofar. Aside from fasting, which is real and physical, not symbolic, everything else that sets the Yom Kippur apart is liturgical, services that last for many hours, melodies used at no other time of year, lots of penetential prayers where people beat their chests symbolically (no infliction of pain is expected), and the reading of the book of Jonah.