My daughter wanted a Carousel Cake Design for her 4th birthday party. My husband and I decided it HAD to go around and around like a real carousel. With a little work it did! The cake was the easy part. I baked two round chocolate cakes. The recipe on the Hershey's Cocoa box is the yummiest ever! I iced it with white icing and used cans of red, yellow and green icing and M&M's to decorate. The top is a plastic lid we had no bottom to and it was a perfect shape, so I decorated it with yellow paint, ribbons pom-pom balls and tiny jingle bells - all of which I had already with my craft supplies. I used a hot glue gun for everything.
I went to a local craft store and bought the wooden horse cut-outs and 'poles' which was just trim. I painted the horses white and smeared some glitter glue on top, then added a bow around the neck. The trim was painted white, as well, and I wrapped a gold, glittery ribbon around it, attaching the ends with hot glue. We, of course measured the poles, by eye-balling it, from the cake plate, added the height of the cake and how far we wanted to stick out of the cake. Nothing scientific.
I flipped the lid upside down, hot glued the poles and then the horse (at different heights to look like they are going up & down). Then I attached the center to the lid, which was not only a decoration, but helped balance the lid. The center was a section of a shipping tube, painted with matching ribbon. It does not go the whole way down into the cake, it just sits on the top. The poles DO go through the cake, down to the bottom.
I bought a Wilson cake plate and the attachable columns to set the cake up on an old record player. We made a box out of white 'cardboard' to hide the record player. The speed of the old record player was perfect and when the guest arrived at the party they were greeted with a Spinning Merry-Go-Round cake!! (I don't have a picture of the cake on the record player, I only took video)