Modularization is a central aspect of software quality, a well-structured hierarchy of classes and packages crucial for maintainability. There is not one perfect package structure, but several measures exists that suggest how a good modularization could look like. The key is to compare these suggested hierarchies to the current hierarchy to improve it. This thesis presents a visualization for comparing one hierarchy to a set of alternative hierarchies of the same underlying items. It is based on icicle plots that are drawn as small multiples. Inner nodes are color coded according to their similarity to nodes of the other hierarchies. The user can select arbitrary sets of leaf nodes to further inspect their cumulative similarity to the nodes of all hierarchies. The visualization is put in context of software modularization by using its terminology and providing features such as to show the source code. It aims to be easy to use once the idea is explained and invites the user to explore the data set.