Final answer:
The phrase 'harmony is vertical' suggests stability and balance in visual arts and music, with vertical elements offering symmetry and structured harmony.
Step-by-step explanation:
The phrase "harmony is vertical" typically refers to the concept within the visual arts and design where vertical elements in an artwork or a composition provide a sense of balance and stability. Similarly, in music, vertical harmony refers to the concept of chords and how different notes combine at a given moment to produce a harmonious sound. In visual arts, organic lines can be seen as tree trunks or columns that offer a stable structure to the design. Symmetrical balance, often seen in nature like in the Moon Jellyfish, and in compositions, is achieved through vertical symmetry, which provides a visually stable and harmonious effect.