Unlike Lego bricks that perfectly assemble next to one another, in many molecular assemblies and modern applications of responsive materials some misfit is almost always present. The constituents of such structures must distort in order to fit next to one another resulting in geometrically frustrated structures that possess no stress-free rest state. The elastic behavior of such structures is thus best described through local intrinsic geometric quantities such as their metric. In this talk, I will discuss the notion of compatibility, geometric frustration and the intrinsic approach as it arises in two-dimensional liquid crystals. I will show that the intrinsic approach does not only accurately describe frustrated states but also allows us to solve inverse design problems that were previously inaccessible.