A design that repeats a motif over and over is called a:

A pattern is a design created by repeating a motif (a single design element) over and over in a regular or planned arrangement. Patterns can be found in textiles, wallpapers, tiles, and many other decorative and functional surfaces. The defining characteristic of a pattern is this systematic repetition of a unit.

The other options describe different principles of art and design. Rhythm in art refers to a sense of visual movement created through repetition or alternation of elements, but it emphasises the flow and tempo rather than the repeated unit itself. Harmony describes the visual agreement or unity among elements in a composition. A focal point is the area of a composition that draws the viewer's attention first, which is the opposite of even repetition.

The key distinction is that a pattern is specifically about a motif being reproduced repeatedly, whereas rhythm, harmony, and focal point describe broader compositional effects.