Description that interprets itself ​

There is also such a type of descriptions, the interpreter of which is embedded, at least partially, in the description itself - you do not need to interpret it with your own brain, the description is interpreted/compiled and executed as it is provided.

This includes any well-designed executable tutorial, any how-to.

Description that becomes a kind of program during execution, which step by step tells you what to do, and after each action tells you how to interpret the result. Well-designed interfaces of programs/websites/etc., which seem intuitive to you, are exactly how they work.