This is about Cocoa, and in particular about class clusters. The problem I wanted to solve was having a class cluster with easily extendable hierarchy without too much interdependency. In my case, I want to create a number of different UITableViewCell descendants, depending on the particular data element the cell should handle. If the data element has a field “string value”, then a UITableViewCell with a text field for such a string value should be created. If the data element has a field “check” representing a yes/no answer, then a UITableViewCell with a yes/no functionality widget should be created instead, and so on. In total, I have less than ten different kinds of UITableViewCell derived classes, but they could become more at any time.