This discourse focuses on the costume design process of “Proof” performed at the T2103 Yao Yi Wei Theater of the National Taipei University of the Arts in November 2021. The paper records the designer's analysis and interpretation of the characters in the play, as well as a detailed description of the outcomes from the arrangements and choices made within a limited timeframe. “Proof” is a play set in the 1990s that explores long-term caregiving within an American family and the feelings of loss experienced by caregivers after the death of the person they cared for. The characters in the play have complex psychological states and unspoken emotional needs, leading to poor communication and ineffective emotional expression. Through using confluence thinking, the designer has integrated the characters' complex psychology with their costumes to convey the characters' inexpressible emotional needs.

The paper thoroughly describes the design development process, from initial script analysis, theme exploration, and character deconstruction to the development of the costume design concept. It includes the step-by-step construction and interpretation of design sketches, production execution, and the final presentation of the costumes on stage.