Twelve years ago, when the girls turned two and four, I surprised them with a castle cake. (Stayed up until the wee hours making it while they were asleep.) Inverted ice cream cones form the towers. I made a second castle cake two years later, for their 4th and 6th birthdays, upon request.
This year, for Annabelle's fourteenth birthday, she wanted to make a castle cake with three of her friends. They were not as concerned about adhering to the formal lines of traditional castle architecture as they would have been as toddlers. They were each more interested in expressing their individual proclivities. One drew a penguin, another a dolphin. In spasms of adolescent glee, they set upon the cake with gel tubes to create a frenzied graffiti. As Roger said, the contrast between the cake made for the two-year-old and the cake made by the 14-year old shows the evolution from princess to punk.
Each girl decorated her own tower, and I found these especially inspired. One of the towers was topped with a lateral Oreo that made it look like something from out of the Jetsons. Since the cookie sheet we had wasn't big enough, they weren't able to affix the towers to the four corners, so they just used them to construct a battlement instead.
Their finished product was a colorful, crazy mash-up of frosting and whimsy: