* hello_world.nit: the standard "hello word" program.
* print_arguments.nit: just repeat the arguments of the program.
* fibonacci.nit: refine Int, the class of all integers, to add a Fibonacci function.
* procedural_array.nit: simple use of arrays without defining new classes.
* clock.nit: a simple class to track time on a wall clock.
* int_stack.nit: simple class for a stack of integers implemented with a linked list.
* clock_more.nit: refine clock to add comparability between clocks.
* circular_list.nit: simple use of generic classes and nullable types to implement a double-linked circular list.
* extern_methods.nit: basic use of extern methods, Nit methods implemented in C code
* callback_monkey.nit|callback_chimpanze.nit: simple example of callback using through FFI.