What term describes an appealing arrangement of shapes and lines in design?

The term that describes an appealing arrangement of shapes and lines in design is 'harmony.' In design principles, harmony refers to the cohesive and pleasing arrangement of various elements. This involves the successful integration of colors, shapes, lines, and textures, creating a unified whole that feels orderly and aesthetically pleasing to the viewer. When elements work well together, they reflect a sense of balance and complement each other, enhancing overall visual appeal.

In contrast, balance refers to the distribution of visual weight in a design, while proportion deals with the size relationships between elements. Rhythm, on the other hand, involves the repetition or alternation of elements that create movement within a design. While each of these concepts is essential to effective design, harmony specifically focuses on the attractive integration and arrangement of different components, making it the most appropriate term for this question.