Human: What are the most common types of wedding cake? Assistant: 
The most common types of wedding cakes are classic, tiered, and sheet cakes. Classic cakes have a single layer of frosting with various decorations such as flowers or ribbons. Tiered cakes usually consist of several layers of buttercream frosting with different colored decorations. Sheet cakes are typically rectangular in shape, made up of many thin layers of buttercream frosting, and can be decorated with intricate designs.