> The type is different. Functions are a class of types. The output of function composition is absolutely a different type but within the class of function type

> The type is different. Functions are a class of types. The output of function composition is absolutely a different type but within the class of function types. I know how types and type constructors work, it's completely irrelevant in the context of what I was trying to say about composition in FP. It seems to me you're probably talking about a very specific technical form of composition. I'm not. To me a simple function like `vertically :: [Ui] -> Ui` is also about composition. The input and output types of the `vertically` function are not the same no, but informally we're still composing UIs into UIs. Which is exactly the level of detail I care for in this discussion.