Several people have created family trees to trace the evolution of programming languages (see, for example, the Mother Tongues chart). Given the news that closures are being added to Objective-C, I'd like to see someone trace the ideas that make up programming languages, such as user-defined data types, generators, forall constructs, and so on. These seem to me to be like "jumping genes" (more properly called "transposons") that can move from one organism to another. Maybe UPL (the Ultimate Programming Language) isn't going to evolve; maybe it's going to accrete...