I spent a lot of time daydreaming about how I would go about creating this cake, and my final thoughts were by using rice Krispy treats as the main hero of this design ;) I was thinking about buying styrofoam, which you can obviously do to save time and ensure you have a sleek, neat finish on your towers. But if you want the entire thing to be edible, I highly recommend rice Krispy treats. They set firm and sturdy, and until today are still completely aligned and fixed exactly where I left them