Emmet Connolly underscores the point that simply having a UI pattern library isn’t enough to create successful work across products at an organization.

To return to our Lego analogy, simply having a limited pattern library of bricks to choose from doesn’t preclude me from building some really crazy shit.

And that’s the difference between having a component library and a full-blown design system. Having a kit of components is of course a good idea, but it’s not enough on its own. A sound design system should also provide rationale, high-level guidelines, philosophy, resources, and more.