The single most important area which Perl now addresses is that of nested data structures and references. And here's a table containing other tables. We now have references and referencing and dereferencing operators to go with them. Furthermore, variables have reference counts on them to control when storage is released. The last demonstrates the most straightforward way to represent C-style structures.
More elaborate methods are also possible.
Multiple level constructs need not be declared - each level is created on the fly if needed, just as assigning something to a scalar variable makes it spring into existence without any previously declaration. You can use more than one of them, in fact, because you could have refs to refs, or functions returning refs. Using Perl's package system, you can write code using object-oriented programming strategies. If there isn't such a method, then a run-time search up the inheritance chain will ensue. If none is found, then an exception would be raised using Perl's exception handling mechanism.