All definitions of perception, cognition, and matter exist within the river of time. The Threshold of Residual Light explores how the very foundation of our perception undergoes profound transformations with the evolution of epochal tools and technology, through the changing symbolism of the color white. Engaging in a repeated dialogue with an AI, Kou Tak-Leong challenges, questions, and demands corrections, forcing it to negotiate between the warm white defined by human sensibility throughout history, and the cool white of modernity. This process of human-machine dialectic yields a multitude of "whites", condensed onto this 2.5-meter-long, slender light strip. No longer a simple color display, the light strip forms an abstract cross-section of a moment in the river of time, with each segment carrying the perceptual definition of a different era.

The optical film applied to the device restricts the viewing angle, so that each moving viewer can only glimpse the "white segment" exclusive to their own position, unable to simultaneously see the visual state observed by others nearby. This "monologue in a public space" mirrors the contemporary individual's condition—intensely connected by digital technology yet simultaneously fragmented.