It is the use of a single color shape size design detail and motif. a single color fashion design. these principles featured in any gradating pattern can be done from the darkest to the lightest tone or from the smallest to the biggest size imparting a rhythmic progression.
The eyes automatically move from looking at the darkest to looking at the lightest tones or vice versa. Sometimes a designer might use a specific shape for accessories in various sizes.
Gradation of the sizes or shapes will tend to bring the eyes from looking at one to looking at the other. The buttons and collar gradate in sizes adding interest to dress.