That's the joke basically... they took the Amiga approach at simplicity. Amazingly, Amiga's UI primitives were nothing but that. Maybe have programmers get a general idea about what the UI needs to feel like and what events are being handled. The simplicity of it is what makes it useful, and these concepts, if you put them into C directly translate to modern systems.

The variables never moved in 30 years. Stop adding visual effects if all you aim for is operational swiftness.