CREATE TYPE function examples

I'm looking for some examples of how the functions for CREATE TYPE
should be. There are none in the documentation, so I was hoping to find
someone here that could help me.
For example, the documentation has this example:

CREATE TYPE box (INTERNALLENGTH = 8,
INPUT = my_procedure_1, OUTPUT = my_procedure_2);

What would the functions my_procedure_1 and my_procedure_2 look like?

Thanks,

-Roberto
--
+----| http://fslc.usu.edu USU Free Software & GNU/Linux Club |------+
Roberto Mello - Computer Science, USU - http://www.brasileiro.net
http://www.sdl.usu.edu - Space Dynamics Lab, Developer
YES!! eh, NO!!! oh, well MAYBE!!!!!!!!