The next part is the code itself, followed by a semi-colon. You will note how the stack it used in this case - a number is pushed on to the stack, then the function pushes a 2 on, and adds them both. A programming language that can be so easily added to is a definite attraction for me as a programmer. While Forth is not as readable as other languages, its power comes in its relative simplicity. Forth is, among other things, a programming language whose ideals are freedom and simplicity.
Freedom requires knowledge and responsibility, and simplicity is yet more demanding.
This is another rather appealing aspect of Forth. Forth is also a great intermediate step between higher-level languages and assembly language. Forth enables you to think at an assembly level with the convience of various higher-level concepts. Forth is capable of. Check out Forth.org for more information on Forth, including a link to download Win32Forth.