I was asked to do one cake for a brother (3 years old) and sister (7 years old) and that the girl's favorites were princesses, reading, music and dance...and the boy loved cars...so this is what I came up with. The girls side of the cake has a castle, and the sides of the cake has ballet slippers and little books. On the top, the music notes turn into a street with cars on the boys side of the cake.