The ability to freely combine smaller programmed artifacts into larger ones, to accomplish larger goals

There exist building blocks which span a range of useful combinations. Composability is, in a sense, key to the notion of “programmability” and every programmable system will have some level of composability

See also: emergent behaviour

Mediums versus Tools

Linus Lee on Browsers as Tools of Thought

A tool is something that takes an existing workflow, and makes it more efficient. A nail is an efficient way of holding pieces of wood together; a to-do app is an efficient way of remembering your responsibilities. A medium, on the other hand, gives us new agency or power by which we can do something we couldn’t do before.

The best mediums are instead collections of generic, multi-purpose components that mesh together well