Roger will present one approach to Language Oriented Programming in F#, a technique in which software designers borrow techniques from language design to organize software architectures. In this approach, simple embedded DSLs called combinator libraries are explored. Roger will show two combinator libraries, one for managing a build process, the other for creating complex 3D visualizations. Attendees will see how the combinator library approach can be applied to these two very different problems. Essentially, a combinator library encourages the designer to break down a problem into elementary pieces and provide ways to recursively compose and reuse these pieces into an abstract description of a problem. Attendees will see a real world example of functional software design, see the use of DSLs and functional design to make the code more readable and provide modularity, see a demonstration of concise techniques for dealing with metadata in one tenth of the code and see how this obviates whole classes of runtime errors at compile time.