That is because the pan sizes used for both cakes are different. So how does one know which pan size to use for which cake? A general deciding factor for this is the design. If the design is extensive for the front side of the cake, like in the mermaid one which has the name as well as many sea elements to go on the very front of the cake, then having a taller cake will serve me right for having more space to arrange everything decently. For the case of spider man cake, the sides had minimal des